Ukrainian President Volodymyr Zelensky on Wednesday promised "victory" on a visit to the strategic city of Izyum that was recently recaptured from Russia by Kyiv's army in a lightning counter-offensive.
The visit came at a decisive moment in Russia's six-month-old invasion, with Ukraine expelling Moscow's forces from swathes of the east and seriously challenging the Kremlin's ambition to capture the entire Donbas region.
"Our blue-yellow flag is already flying in de-occupied Izyum. And it will be so in every Ukrainian city and village," Zelensky said in a statement on social media.
"We are moving in only one direction -- forward and towards victory."
Pictures distributed by his office showed the Ukrainian leader wearing dark green and flanked by guards as he took selfies with soldiers and thanked troops at a flag-hoisting ceremony.
Back in Kyiv, a motorist collided with a vehicle carrying Zelensky, though the president was not seriously injured in the accident, his spokesman said Thursday.
"The law enforcement officers will investigate all the circumstances of the accident," the spokesman added.
In his nightly address, a video of which was posted shortly after the accident, Zelensky said that "almost the entire region (of Kharkiv) is de-occupied".
"It was an unprecedented movement of our soldiers -- the Ukrainians once again managed to do what many thought was impossible."
Ukraine has recently claimed sweeping successes in the northeastern Kharkiv region that borders Russia, and has said it has clawed back territory along a southern front near the Kherson region on the Black Sea.
Zelensky said Wednesday that Russia's occupation of Crimea -- annexed by Moscow in 2014 -- was a "tragedy" and promised that his forces would eventually recapture the peninsula.
Ukrainian forces in Kharkiv have since September 6 recaptured around 8,500 square kilometres (3,200 square miles) and areas home to some 150,000 people, said deputy foreign affairs minister Ganna Maliar.
- 'They killed my son' -
In the reclaimed 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 afraid," he said.
Wiping tears from her eyes with a veil, Mykola's mother Nina said: "I cry every day. They killed my son."
Moscow said its forces were hitting back on areas recaptured in Kharkiv with "massive strikes", and also claimed to have captured dozens of Ukrainian servicemen in the southern Kherson and Zaporizhzhia regions.
Ukraine's presidency warned Wednesday that floods could hit the city of Kryvyi Rih -- Zelensky's hometown -- after a Russian strike damaged infrastructure, causing the Inhulets River to flood.
The centre and another district of the city of 600,000 people were at risk of flooding, said Kyrylo Tymoshenko, deputy head of the president's office.
The head of the Kryvyi Rih military administration, Oleksandr Vilkul, said in a statement: "In order to avoid unnecessary risks, I kindly ask the residents of certain streets to evacuate."
German Chancellor Olaf Scholz, meanwhile, disclosed Wednesday the contents of a 90-minute telephone conversation with Vladimir Putin, saying the Russian leader did not feel he had made a mistake in invading Ukraine.
"There was no indication that new attitudes are emerging," he said of Tuesday's conversation.
The Kremlin said Putin himself had discussed getting Ukrainian grain to those most in need in a telephone conversation with UN chief Antonio Guterres.
"Both sides emphasised the importance of meeting the needs, as a priority, of those in Africa, the Middle East and Latin America who need food," said a statement from his office Wednesday.
The Kremlin, which has made little mention of the setbacks in recent days, vowed to continue fighting, claiming that the perceived threat Kyiv posed to Russia remained.
- 'Life and death' -
The Ukrainian official in charge of the eastern Donetsk region, partially controlled by pro-Moscow separatists since 2014, said Russian forces had attacked the entire frontline region over the past 24 hours.
Pavlo Kyrylenko, the Donetsk governor, said one civilian had been killed and again urged all others to leave, describing the order as a "matter of life and death".
Military observers have credited the success of Ukraine's pushback into the east to Western-supplied arms, particularly long-range precision artillery, and on the training of Ukrainian forces by Western allies.
The Ukrainian military announced on social media Wednesday that some 5,000 Ukrainian military personnel had been trained as part of a joint programme with the United Kingdom.
Western countries have also hit back against Russia with waves of economic sanctions.
EU commission president Ursula von der Leyen on Wednesday said the successive packages of EU measures against Russia for its invasion of Ukraine were "here to stay", while calling on Europeans to maintain their resolve.
She also told MEPs that she would travel Wednesday to Kyiv to meet Zelensky.