• The pressure is now on Kyiv to maintain the momentum in its counteroffensive.
• Western governments have hailed Ukraine's "significant progress" in the war.
• Kyiv announced it had reclaimed more than 3,000 square miles of Russian-occupied territory in the east and south of the country since the start of September.

After Ukraine's stunning successes in recapturing Russian-occupied territory in northeast and southern Ukraine over the last week, the pressure is now on Kyiv to maintain the momentum in its counteroffensive.

Western governments have hailed Ukraine's "significant progress" in the war after Kyiv announced it had reclaimed more than 8,000 square kilometers (3,088 square miles) of Russian-occupied territory since the start of September.

Ukraine's counterattacks prompted Russian forces to retreat from the Kharkiv region in the northeast of the country while Kyiv announced that the Ukrainian flag was once again being raised in hundreds of villages across the area.

President Volodymyr Zelenskyy proclaimed Wednesday that "we are moving in only one direction — forward and towards victory."

The question on everyone's lips now is whether this chapter marks a definitive turning point in the war, and what comes next. Officials in the country are understandably cautious about showing Kyiv's hand.

"We hope this is a starting point," Yuriy Sak, an advisor to Ukraine's defense minister, Oleksii Reznikov, told CNBC on Wednesday.

"We are normally cautious about making any predictions, and it's always safer to say certain things after they occur, but anyway, what has happened is in many respects unexpected even for us," Sak added.

"Indeed, it was a very successful campaign, the Ukrainian army was able to regain control of over 8,000 square kilometers. That's a huge part of the territory that was temporarily occupied by the Russians and as a result, what we're seeing is that the Russian army is demoralized, its military capabilities are degraded."

Progress, then what?

Ukraine's forces have been able to recapture dozens of towns and villages in the northeast of the country over the last few days, including the strategically important towns of Izyum and Kupiansk.

Ukraine's counterattacks in the northeast came after Russia redeployed troops away from the region to defend areas they occupied in the south after Ukraine heavily signaled it would launch a counteroffensive around the port city of Kherson.

U.S. President Joe Biden hailed the "significant progress" Ukraine had made in the last week but said it was "hard to tell" if it was a turning point in the conflict, which has been raging since Feb. 24.

"The question is unanswerable. It's hard to tell. It's clear the Ukrainians have made significant progress. But I think it's going to be a long haul," he said Tuesday.

In Europe, meanwhile, the head of the European Commission, Ursula von der Leyen, praised Ukraine's advances and reiterated the region's commitment to supporting Ukraine for "the long haul," noting Wednesday that "we have seen in the last days the bravery of Ukrainians paying off."

Sak told CNBC that Ukraine's armed forces "will keep the momentum" in the conflict, planning more counteroffensive operations both in the northeast and the south.

Nonetheless, he noted, that "at the same time, we understand who we are dealing with, right? So this is an army of war criminals, and [a] genocidal army, they've not stopped the missile terror."

"What can be said with certainty is that, at this stage, probably more than ever, we need more support from our international partners in terms of providing us with weaponry, tanks, armored vehicles, combat aircraft, and, of course, defense systems and anti-rocket systems. These are all things that we need to use this momentum, to keep them going to protect our cities and to drive the enemy out."

Kremlin criticism

Russian forces responded to Ukraine's wins in recent days by pummeling Kharkiv's energy infrastructure with missile attacks and knocking out water and power supplies in the process.

Still, it's undoubted that a number of Russia's forces now appear to be on the back foot in parts of Ukraine, with Zelenskyy saying some were fleeing back across the border to Russia.

Analysts say that Ukraine's advances will have shaken the Kremlin and believe that Russian President Vladimir Putin's regime is looking more fragile this week.

With previous failures in Ukraine, such as the retreat from Kyiv in April or the withdrawal from Snake Island, a strategic outpost in the Black Sea, Russia has sought to downplay these maneuvers, largely saying they were due to Russia's forces "regrouping" or being "redeployed" elsewhere.

This time, with even pro-Kremlin commentators criticizing the latest setbacks on the battlefield, it appears to be different.

"Kremlin officials and state media propagandists are extensively discussing the reasons for the Russian defeat in Kharkiv Oblast, a marked change from their previous pattern of reporting on exaggerated or fabricated Russian successes with limited detail," analysts at the Institute for the Study of War said Tuesday.

The ISW noted that the Russian Ministry of Defense's original explanation for its failure in Kharkiv, claiming its forces were withdrawing from the region to "regroup," had faced "quick and loud criticism online" and that the Kremlin's acknowledgment of the defeat was now "part of an effort to mitigate and deflect criticism for such a devastating failure away from Russian President Vladimir Putin and onto the Russian Ministry of Defense and the uniformed military command."

Kremlin sources "are now working to clear Putin of any responsibility for the defeat, instead blaming the loss of almost all of occupied Kharkiv Oblast on underinformed military advisors within Putin's circle," it said.

Shoigu the 'fall guy'

It's now very likely that Russia's defense minister, Sergei Shoigu, will become Putin's "fall guy," one analyst told CNBC on Tuesday.

"This is an embarrassing defeat for the Russians," said Samuel Ramani, a geopolitical analyst and associate fellow at the Royal United Services Institute, adding that there would be a push in Moscow to blame Russia's Ministry of Defense for failings in the campaign in Ukraine.

"There's a lot of recriminations and internal talk [in Russia about the military failures], but we shouldn't view this as a sign that Putin is getting weaker. The focus needs to be mostly on the Defense Ministry," he noted.

"Putin will keep Shoigu there to take the criticism and take the heat, while he keeps shuffling and firing lower-level commanders. Already we've seen in six weeks two commanders get fired in the western military district alone. ... So Putin is not weak right now, the criticism isn't going to him, it's going to the Defense Ministry," Ramani said.