Sunday, Ukrainian forces successfully launched a quick counteroffensive in the northeast of the country, forcing Russian battalions to evacuate.

As the war marked 200 days on Sunday, Ukraine's swift effort to retake Russia-occupied territories in the northeastern Kharkiv region caused Moscow troops to evacuate to avoid being besieged, leaving behind a considerable number of weapons and munitions.

In a late-Saturday video message, the ecstatic Ukrainian president Volodymyr Zelenskyy taunted the Russians, stating that "the Russian army in these days is demonstrating the best that it can do — showing its back."

On Sunday, he uploaded a video of Ukrainian forces raising the national flag over Chkalovske, another Russian-held town they recaptured during the counter-offensive.

General Valerii Zaluzhnyy, the head of the Ukrainian military, stated on Sunday that Ukraine had liberated around 3,000 square kilometers since the beginning of September.

He said that the Ukrainian army is currently less than 50 kilometers from the Russian border.

The Russian retreat marked the greatest military victory for Ukrainian forces since they blocked a Russian assault to capture Kyiv at the beginning of the nearly seven-month conflict.

Moscow was caught off guard by Ukraine's onslaught in the Kharkiv region, as it had transferred numerous troops from the region to the south in anticipation of the main Ukrainian counteroffensive there.

In an uncomfortable attempt to save face, the Russian Defense Ministry stated on Saturday that the evacuation of troops from Izyum and other locations in the Kharkiv region was designed to bolster Russian forces in the adjacent Donetsk region to the south.

The allegation resembled the justification Russia provided earlier this year for withdrawing its forces from the Kyiv region after failing to capture the capital.

Separatist Strelkov ridicules the retreat as Russian commentators criticize the government

The group of Russian forces surrounding Izyum has been crucial to Moscow's efforts to conquer the Donetsk region, and its withdrawal will significantly weaken Russia's capacity to launch an offensive against the Ukrainian strongholds of Sloviansk and Kramatorsk, located close to the south.

Igor Strelkov, who led Russia-backed separatists in the early months of the Donbas conflict when it erupted in 2014, mocked the Russian Defense Ministry's explanation of the retreat, suggesting that handing over Russia's territory near the border to Ukraine was a "contribution to Ukrainian settlement"

Russian military bloggers and nationalist commentators decried the retreat as a severe setback and urged the Kremlin to respond by intensifying its war efforts.

Despite the catastrophe in Ukraine, many harshly criticized Russian authorities for continuing Saturday's opulent celebrations in Moscow, which honored a city holiday with fireworks and other extravagant activities.

Russian President Vladimir Putin attended the opening of a massive observation wheel in a Moscow park, a new transport link, and a sports arena while Russian forces withdrew swiftly from Izyum while under fire from Ukrainian forces.

The action highlighted the Kremlin's efforts to maintain the illusion that the war it insists on labeling a "special military operation" is proceeding according to plan without impacting the country's condition.

Sergei Markov, a pro-Kremlin political analyst, criticized the celebrations in Moscow as a severe political error.

Markov stated on his messaging app channel, "The fireworks in Moscow on a tragic day of Russia's military defeat will have extremely serious political consequences," "Authorities mustn't celebrate when people are mourning."

In an indication of a potential rupture in the Russian leadership, Ramzan Kadyrov, the Kremlin-backed leader of Chechnya, stated that the retreat from the Kharkiv region was the consequence of military missteps.

Kadyrov stated, "They have made mistakes, and I think they will draw the necessary conclusions," Kadyrov stated, "If they don't make changes in the strategy of conducting [the war] in the next day or two, I will be forced to contact the leadership of the Defence Ministry and the leadership of the country to explain the real situation on the ground,"

Saturday in televised remarks, Ukrainian Defense Minister Oleksii Reznikov stated that the Russians have been cut off from their supply lines and projected further successes.

He predicted a Russian counterattack by comparing it to an avalanche. "One line of defense will shake, and it will fall."

Despite Ukraine's successes, US Secretary of State Antony Blinken and NATO's chief cautioned on Friday that the conflict will likely continue for months. Blinken stated that the conflict was entering a critical phase and asked Ukraine's Western supporters to maintain their aid throughout what might be a challenging winter.