Ukrainian President Volodymyr Zelenskyy vowed a “victory” on Wednesday during a visit to the strategic city of Izyum, which was recently retaken from Russia by the Kiev army in a blitz counter-offensive.

The visit comes at a crucial time in Russia’s six-month invasion, during which Ukraine is driving Moscow’s forces out of parts of the east and seriously undermining the Kremlin’s ambitions to conquer all of Ukraine’s Donbass region.

“Our blue and yellow flag is already flying in occupied Izyum. And it will be so in every Ukrainian city and village,” Zelenskyy said in a statement on social media.

“We are only moving in one direction – forward and to victory.”

Pictures distributed by his office showed the Ukrainian leader dressed in dark green and flanked by guards as he took selfies with soldiers and thanked the troops at a flag-raising ceremony.

Ukraine has enjoyed resounding gains in recent days in the northeastern Kharkiv region, which borders Russia, and also says it has regained territory along a southern front near the Black Sea region of Kherson.

Zelenskyy said Wednesday that Russia’s occupation of Crimea – which Russia annexed in 2014 – was a “tragedy” and vowed his forces would eventually retake the peninsula.

Kyiv says its forces have since early September recaptured hundreds of villages and towns seized by Russian forces that invaded Ukraine on February 24.

In the recaptured eastern Ukrainian village of Bogorodychne, 58-year-old Mykola told AFP he “barely survived” the Russian occupation during which his brother was killed.

“How can I describe it in words? It was difficult. I was scared,” he said.

Mykola’s mother Nina wiped tears from her eyes with a veil and said:

“I cry every day. They killed my son.”

Moscow said its forces were retaliating with “massive strikes” on recaptured areas in Kharkiv and – without providing evidence – claimed to have inflicted losses on Ukrainian military equipment and soldiers.

In a battlefield update Wednesday, Russia also claimed to have captured dozens of Ukrainian soldiers in the southern Kherson and Zaporizhia regions.

The Kremlin, which made little mention of setbacks in recent days, vowed to keep fighting, claiming that the perceived threat to Russia from Kyiv remains.

“The leadership of this country must take action to eliminate threats to the Russian Federation,” President Vladimir Putin’s spokesman Dmitry Peskov told journalists.

The Ukrainian official in charge of the eastern Donetsk region, which has been partially controlled by pro-Moscow separatists since 2014, said Russian forces had attacked the entire frontline region in the past 24 hours.

Pavlo Kyrylenko, the Donetsk governor, said one civilian had been killed and again urged everyone else to leave the country, describing the order as a “matter of life and death”.

Military observers have attributed the success of Ukraine’s push back east to western-supplied weapons, particularly long-range precision artillery and also the training of Ukrainian forces by western allies.

The Ukrainian military announced on social media on Wednesday that about 5,000 Ukrainian military personnel had been trained under a joint program with the United Kingdom.

Western countries have also hit back with waves of economic sanctions against Russia.

European Commission President Ursula von der Leyen said on Wednesday successive waves of EU sanctions against Russia over its invasion of Ukraine would continue and that Europeans must remain firm in their dealings with Moscow.

“I want to be very clear that sanctions are here to stay. This is the time for us to show determination, not appeasement,” von der Leyen said in the European Parliament during her annual State of the Union address.

Ukraine’s First Lady Olena Zelenska attended the gathering in Strasbourg and received a standing ovation from lawmakers.

She also told MPs that she will travel to Kyiv on Wednesday to meet with Ukrainian President Volodymyr Zelenskyy.