This was CNBC's live blog tracking developments on the war in Ukraine on June 6, 2022. See here for the latest updates. 

Ukraine's President Volodymyr Zelenskyy has said that an air alert was announced over almost the entirety of Ukraine last night, raising civilian anxiety. Meanwhile in Russia, the Parliament has given its initial approval to measures that put Russia's economy on a war footing.

Sloviansk, a city in Donetsk that has found itself on the front line as Russian forces advance, has become the focus of Russian aggression in recent days. The British Defense Ministry said the battle for the city will be the "next key contest" for Ukraine.

The city's mayor has urged civilians to evacuate as quickly as they can as Russian forces approach the city. Yesterday, a market in the center of the city was shelled, killing two people and injuring seven others.

Russia has turned its attention to capturing more parts of the Donetsk region of the Donbas, having already seized the neighboring Luhansk province. Donetsk is now experiencing heavy shelling, the same strategy that Russian forces used in Luhansk. Sloviansk, Kramatorsk and Bakhmut are now Russia's key targets.

Russia earns approximately $1 billion a day in export revenues from oil and gas, expert says

Despite a slew of coordinated global sanctions, Russia still brings in about $1 billion a day in export revenues from oil and gas.

In the weeks since Russia invaded Ukraine, Washington and its allies have imposed rounds of coordinated penalties that vaulted Russia past Iran and North Korea as the world's most-sanctioned country.

However, Russia still receives significant revenues from energy exports, according to research compiled by Gerard DiPippo, a senior fellow at the Economics Program at the Center for Strategic and International Studies.

DiPippo found that oil and gas accounted for 47% of Russia's revenues from January to May this year. And while Russian oil production fell in April, revenues increased by 80%.

"For comparison, Russian fiscal data suggests that Moscow spent $325 million per day on military expenditures in April, the latest data available," DiPippo writes, referencing Moscow's ability to still finance its war in Ukraine.

— Amanda Macias

Celebrity chef and humanitarian Jose Andres shares video of long food lines in Ukraine

Spanish celebrity chef and restaurateur Jose Andres shared a video on Twitter of what he said was a food distribution point in Mykolaiv, Ukraine.

"This is one of our distribution points today … line stretched around the block but moved quick! Many refugees here, plus elderly who cannot leave," wrote Andres, who founded the World Central Kitchen, a humanitarian organization dedicated to feeding vulnerable communities.

Andres added that more than 12,000 meals are cooked and delivered by the World Central Kitchen a day in Mykolaiv.

The two-star Michelin chef brought the World Central Kitchen, to Ukraine in order to address the mounting food crisis triggered by Russia's war.

— Amanda Macias

Blinken speaks to Ukraine's Kuleba ahead of G-20 meeting

Secretary of State Antony Blinken spoke today with Ukrainian Foreign Minister Dmytro Kuleba ahead of the G-20 foreign minister meeting in Bali, Indonesia.

"The Secretary condemned Russia's atrocities in Ukraine and provided updates on multilateral efforts to resolve Russia's military blockade of agricultural exports from Ukraine's ports," according to a State Department readout of the call. 

Blinken also updated his Ukrainian counterpart on additional U.S. security assistance and previewed further financial support for Ukraine.

— Amanda Macias

Nearly two-thirds of Ukraine’s children have been displaced by war, UNICEF official says

The UN says that nearly two-thirds of Ukraine's children have been displaced since the start of Russia's war in late February.

"I would say every single child in Ukraine, their lives have been touched by this war. They've either lost a family member or they have either witnessed trauma themselves," explained Afshan Khan, the regional director for the UN Children's Fund, or UNICEF, to reporters at the United Nations.

"With two-thirds of the children in the country on the move, we cannot say that a single child's life has not been touched," added Khan.

Khan also said that the staggering number of schools destroyed by Russian strikes in Ukraine presents another grim challenge for child development.

— Amanda Macias

France beefs up training with NATO allies along Ukraine's borders

The French military released a map detailing its commitment to bolstering the security of NATO's eastern flank amid Russia's ongoing war in Ukraine.

French jets and surveillance aircraft are conducting patrol missions over Poland, Slovenia and Slovakia while French troops carry out a training mission dubbed "Aigle" in Romania alongside Belgian, Dutch and Romanian forces.

In Russia's backyard, French forces are carrying out training exercises in Estonia dubbed "Thunder Lynx." The training scenario is aimed at deploying an airborne force from France to Estonia in less than six hours.

French troops are also deployed in NATO member countries along Ukraine's borders.

— Amanda Macias

Biden and Harris speak to wife of WNBA star Brittney Griner

President Joe Biden and Vice President Kamala Harris spoke with Cherelle Griner, the wife of WNBA star Brittney Griner who is wrongfully detained in Russia, according to a White House readout of the call obtained by NBC News.

Biden reassured her that he is working to secure her wife's release as soon as possible, as well as the release of Paul Whelan and other U.S. nationals wrongfully detained in Russia as well as around the world.

He also read her a draft of a letter he plans to send to Griner today.

Earlier in the week, Griner wrote a letter to Biden asking for his help with her case in Russia. The 31-year-old Olympian, who is currently on trial in Moscow, was arrested in February on accusations of smuggling hashish oil, a charge that carries up to 10 years in prison. Griner plays professional basketball in Russia during the WNBA offseason.

"I'm terrified I might be here forever," Griner wrote to Biden.

Biden's phone call comes on the heels of National Security Advisor Jake Sullivan and Secretary of State Antony Blinken's discussions with Cherelle.

 — Amanda Macias

Estonia welcomes Sweden and Finland into NATO following parliament ratification

Estonia's Minister of Defense Kalle Laanet welcomed the decision of the Estonian Parliament to ratify Finland and Sweden's ascension protocols to the NATO alliance, a crucial step that brings the two countries closer to joining the military group.

Estonia, which is about twice the size of New Jersey, sits on the Baltic Sea and shares a border with Russia and NATO ally Latvia.

"It is important to note that Finland and Sweden joining NATO will certainly strengthen the security of the Baltic Sea region," Laanet wrote in a statement. "NATO's military posture on land, sea and air will increase significantly and NATO's intelligence, cyber and other capabilities will be strengthened in our region," he added.

In May, both nations began the formal process of applying to the NATO alliance.

— Amanda Macias

More than 150 cultural sites in Ukraine have been partially damaged or destroyed

More than 150 cultural sites in Ukraine have been partially or totally destroyed as a result of Russia's war in Ukraine, according to a tally compiled by UNESCO.

United Nations experts identified 152 cultural sites, including 70 religious buildings, 30 historical buildings, 18 cultural centers, 15 monuments, 12 museums as well as seven libraries.

The majority of the damaged cultural sites are located in Donetsk, Kharkiv and in Kyiv.

"These repeated attacks on Ukrainian cultural sites must stop. Cultural heritage, in all its forms, should not be targeted under any circumstances," wrote Audrey Azoulay, Director-General of UNESCO in a statement.

 — Amanda Macias

British foreign secretary urges NATO allies to bring Finland and Sweden into Article 5 umbrella

British Foreign Secretary Liz Truss urged NATO allies to bring Sweden and Finland into the alliance's Article 5 umbrella "as swiftly as possible."

"Both countries' decision puts them at risk of a potentially aggressive Russian response. Russia has already made several threatening comments in the public domain regarding the possibility of Swedish and Finnish membership of NATO," Truss wrote in a statement.

The 30-member-strong alliance has consistently warned Russian President Vladimir Putin that an attack on one NATO member state will be viewed as an attack on all, triggering the group's cornerstone Article 5 mutual defense clause.

To date, the 30-member alliance has only invoked Article 5 once — in defense of the United States in the wake of the 9/11 terrorist attacks.

— Amanda Macias

Biden slated to respond to WNBA star Brittney Griner, White House officials tell NBC News

President Joe Biden is expected to respond to WNBA star Brittney Griner as soon as today, administration officials tell NBC News.

Biden's response comes on the heels of a handwritten letter she penned on Monday asking him for help with her case in Russia.  

The 31-year-old Olympian, who is currently on trial in Moscow, was arrested in February on accusations of smuggling hashish oil, a charge that carries up to 10 years in prison. Griner plays professional basketball in Russia during the WNBA offseason.

"I'm terrified I might be here forever," Griner wrote to Biden.

On Tuesday, White House press secretary Karine Jean-Pierre said Biden had read Griner's letter. She added that the administration has been working aggressively behind the scenes and through diplomatic channels for Griner's release.

— Amanda Macias

Russian military claims it has destroyed two U.S.-made HIMARS

Russia's Ministry of Defense has claimed that it has destroyed two U.S.-made High Mobility Artillery Rocket Systems, better known as HIMARS.

"High-precision air-based missiles have destroyed 2 U.S.-made Himars multiple-launch rocket launchers and 2 ammunition depots near Malotaranovka in Donetsk People's Republic," the ministry claimed in its latest military update on Wednesday.

CNBC and NBC News have not been able to immediately verify the claim, nor a video that the ministry has shown claiming to be the strike on the HIMARS.

If verified, however, the destruction would be a blow for Ukraine as it has only just been sent a small number of the weapons from the U.S. In total, the U.S. said it would send eight HIMAR systems to Ukraine with some arriving in the last few weeks, according to Ukraine's defense minister, who said some had arrived on June 23.

HIMAR systems are seen as a potential game-changer in Ukraine's resistance against Russia's advances in Ukraine, particularly in the east, with the U.S. Department of Defense announcing in early June that it would be giving Ukraine four such systems that allow for the launching of multiple long-range, precision-guided rockets.

Ukraine's army celebrated the HIMAR as "beautiful, fast [and] accurate" in a tweet earlier this week showing the rocket systems in use.

Neither the U.S. nor Ukraine has commented on Russia's claim.

— Holly Ellyatt

Ukraine tries to hold back Russian forces at the border of Donetsk

Ukrainian forces are trying to hold back Russian fighters at the border between the neighboring regions of Luhansk and Donetsk regions, according to Serhiy Haidai, the head of Luhansk Regional Military Administration.

Haidai said on Telegram Wednesday that the Russian occupiers were suffering "significant losses" as they tried to advance from one region, which they captured last weekend, into Donetsk as part of their mission to, as Moscow calls it, "liberate" the Donbas.

He said Russian forces had been trying to advance toward Donetsk but had been cut off at the Bakhmut-Lysychansk highway, running near Bilohorivka. "Under the pressure of our defenders, the enemy was forced to retreat," Haidai wrote.

The official said that Russian forces were not able to carry out orders to advance because of "significant losses in terms of personnel."

"During the assault on Lysychansk alone, thousands of Russian soldiers were killed and injured. In addition, Russian occupiers are facing problems with ammunition supplies, as the Ukrainian military have destroyed several ammunition depots in the occupied areas in recent weeks," Haidai said.

Haidai was confident that Russia's advantage in terms of the number of personnel would be reduced as soon as the Ukrainian military receive more long-range weapons.

— Holly Ellyatt

Kremlin slams France's decision to release Macron-Putin phone call comments

Russia's Foreign Minister Sergei Lavrov has criticized the publication of fragments of phone conversations between President Putin and his French counterpart Emmanuel Macron.

"I think that diplomatic ethics, of course, does not imply such a one-sided leak of records," the minister told reporters following his visit to Vietnam, according to comments reported by state news agency Ria Novosti.

A diplomatic rift has arisen between Moscow and Paris following the release of a documentary in France in which excerpts of a phone conversation between the presidents that took place on Feb. 20 were revealed.

The excepts included the Russian president complaining about the Ukrainian government, saying it was not "democratically elected" and Putin also saying he was speaking to Macron — who was trying unsuccessfully to persuade him to meet President Joe Biden in Geneva — from the gym.

Moscow has slammed the apparent breach of diplomatic norms, despite having itself published diplomatic correspondence between Russia, France and Germany over Ukraine last November.

On Wednesday, Lavrov tried to defend Russia's actions in light of the latest spat with France, saying that "before we published the content of my talks with colleagues from France and Germany, we warned them three times that if we do not get clear explanations why they refuse the documents agreed upon with their direct participation, we will be forced to make public," he said.

— Holly Ellyatt

Russia's Chechen allies vow to fight until Putin stops them

The Chechen allies of President Vladimir Putin have vowed to continue fighting in Ukraine, saying they would even go beyond the country, until the president stops them.

"There should be no doubt: The DPR [the Donetsk People's Republic — a pro-Russian breakaway region], Mykolaiv, Kherson, Odesa, until Vladimir Vladimirovich Putin stops us. Inshallah [God willing] we'll get to Berlin," Chechen Parliament speaker Magomed Daudov told reporters.

Pro-Russian Chechen fighters have been part of Russia's forces in Ukraine and have a fearsome reputation in battle, being experienced in urban combat following several conflicts with Russia itself in the '90s and 2000s before a rapprochement between Chechen leader Ramzan Kadyrov and Putin a few years ago.

It's doubtful that Daudov's comments reflect any official policy in Moscow. There are also Chechens fighting for Ukraine.

— Holly Ellyatt

The battle for Sloviansk is fast approaching, UK says

Britain's Ministry of Defense said a battle for the major city of Sloviansk on the front line in Donetsk is coming. Russian forces are advancing into the province of Donetsk following their capture of neighboring region Luhansk.

"Russian forces from the Eastern and Western Groups of Forces are likely now around 16 km north from the town of Sloviansk. With the town also under threat from the Central and Southern Groups of Forces, there is a realistic possibility that the battle for Sloviansk will be the next key contest in the struggle for the Donbas," the ministry said on Wednesday.

A market in Sloviansk was struck yesterday, killing two people and injuring seven others, the city's mayor, Vadym Lyakh, said Wednesday.

The ministry noted that Russia is likely continuing to consolidate its control over Lysychansk and the Luhansk Oblast (province) where there has been severe fighting for weeks on end, culminating last weekend with Russia's capture of the last Ukrainian-held city in the province.

To the north of Sloviansk, the British noted, Russia has "committed most of the remaining available units from the Eastern and Western Groups of Forces to the Izium axis," referring to the route between Sloviansk via Izium, to Kharkiv in the northeast of Ukraine.

"Over the last week, Russian forces have likely advanced up to another 5 km down the E40 main road from Izium, in the face of extremely determined Ukrainian resistance," the ministry said.

— Holly Ellyatt

Russia looks to mobilize economy to sustain war

Russia's Parliament has taken several steps toward putting the country's economy on a war footing, with two bills being passed in the State Duma (the lower house of Parliament) that would allow the government to compel Russian businesses to supply the military with goods for the war effort.

"The load on the defense industry has increased significantly. In order to guarantee the supply of weapons and ammunition, it is necessary to optimize the work of the military-industrial complex and enterprises that are part of cooperation chains," Deputy Prime Minister Yuri Borisov told lawmakers Tuesday, according to a Reuters translation.

A second bill, also passed by the Duma after an initial reading, would amend the labor code. That means businesses supplying goods that assist the war effort could make their employees work at night, on weekends and holidays, and without annual leave, if necessary.

Both bills still need to undergo second and third readings in the Duma and must be approved by the upper chamber and signed off by President Vladimir Putin.

"The mobilization of the country's economic and industrial potential to support the military is a tacit acknowledgment of significant losses incurred since the start of the invasion and approaching shortages of certain types of equipment," Andrius Tursa, Central and Eastern Europe advisor at Teneo Intelligence, commented Tuesday.

"At the same time, Moscow could be seen as preparing to sustain its military operations in the longer run."

— Holly Ellyatt

Air alert sounded over almost all of Ukraine, raising civilian anxiety, Zelenskyy says

Ukraine's President Volodymyr Zelenskyy said an air alert was announced over almost all of Ukraine on Tuesday night, leaving many civilians anxious after a period of relative calm in parts of the country.

"Before that, there had been no air alert in the capital and some regions for some time," Zelenskyy said in his nightly address, adding that this had left many people wondering whether Russia was planning something.

Zelenskyy told Ukrainians not to "overthink," saying, "you should not look for logic in the actions of terrorists."

"The Russian army does not take any breaks. It has one task — to take people's lives, to intimidate people — so that even a few days without an air alarm already feel like part of the terror."  

— Holly Ellyatt

Mounting evidence of Russian war crimes in Ukraine, UN says

UN High Commissioner for Human Rights Michelle Bachelet said that her office has mounting evidence of Russian forces carrying out unlawful killings and summary executions.

"Growing evidence gives my office reasonable grounds to believe that serious violations of international humanitarian law in this regard have been committed by Russian armed forces," Bachelet wrote in a statement.

Bachelet said that UN investigators have verified the recovery of more than 1,200 civilian bodies from Kyiv. She added that her office is working to corroborate more than 300 allegations of killings by Russian armed forces in situations that were not linked to active fighting.

"The arbitrary detention of civilians has also become widespread in territory controlled by Russian armed forces and affiliated armed groups. Despite restrictions on access, we have documented 270 cases of arbitrary detention and enforced disappearance," she added.

The Kremlin has previously denied that its forces have committed crimes against civilians in Ukraine.

— Amanda Macias

U.S. and allies call for suspension of Russia and Belarus from international sports, ban on official state flags at athletic events

The State Department reiterated its calls for the international sports community to suspend Russian and Belarusian sports organizations and remove Russian and Belarusian individuals from positions of influence associated with the athletic community.

"National and international sports organizations should consider suspending the broadcasting of sports competitions into Russia and Belarus," the State Department wrote in a statement adding that "official state Russian and Belarusian flags, emblems and anthems should be prohibited."

"Furthermore, we reiterate our encouragement for the international sport community to continue to show its solidarity with the people of Ukraine, including through supporting the continuation and reconstruction of Ukrainian sport where possible," the State Department wrote in a joint statement with representatives from more than 30 countries.

— Amanda Macias

'Historic day,' NATO chief says as all 30 NATO allies approve Finland and Sweden membership

All 30 NATO member countries approved accession protocols for Finland and Sweden to join the military alliance, a significant step in NATO enlargement.

NATO Secretary-General Jens Stoltenberg welcomed the "historic day for Euro-Atlantic security."

"With 32 nations around the table, we will be stronger and safer, as we face a more dangerous world," Stoltenberg wrote on Twitter.

In May, both nations began the formal process of applying to the NATO alliance.

— Amanda Macias

Pro-Russian forces are heading toward Donetsk, separatist leader says

Pro-Russian separatist forces from the self-styled Donetsk and Luhansk "People's Republics" (known as the DPR and LPR) are moving toward the Donetsk province, the head of the DPR Denis Pushilin said on Tuesday, according to Russian state news agency TASS.

"We can already say that our corps, the first corps that took part and helped our brothers [in the liberation of the LPR], is already moving to the Donetsk direction as well as the second corps [from] Luhansk," Pushilin said.

Russia and its proxies in eastern Ukraine call the capture of the Luhansk region, which happened last weekend, a "liberation" although Russia is widely seen as using a rationale of "protecting" the breakaway separatist areas, which were founded in 2014 as Russia annexed Crimea from Ukraine, as an excuse for invading Ukraine.

— Holly Ellyatt

Read CNBC's previous live coverage here:

UN cites 'growing evidence' of war crimes in Ukraine; Pro-Russia separatist forces descend on Donetsk