UK Prime Minister Keir Starmer told Ukrainian President Volodymyr Zelensky that "Russia must end the continued bloodshed" from the conflict between the two countries.
The UK prime minister spoke to Zelensky during a phone call on Tuesday before leaving for his visit to China and Japan.
A Downing Street spokesperson said visits by ministers to Ukraine showed "unwavering UK support" ahead of next month's fourth anniversary of Russia's invasion and amid the latest round of missile and drone attacks.
The spokesperson said: "The leaders discussed the progress made during recent peace talks in Abu Dhabi and agreed on the need for a just and lasting peace in Ukraine.
"The Prime Minister said that Ukraine has already shown its commitment to peace and that Russia must end the continued bloodshed.
"The Prime Minister said the UK would continue to work closely with international partners to support Ukraine's security."
Zelensky said in a post on X after the call that UK support was "crucial... not only with words but also through concrete energy aid packages".
He said the talks in Abu Dhabi were constructive and would continue later this week, adding that "Ukraine wants to end this was as quickly as possible" and was prepared to work round the clock for peace.
"Russia must show the same readiness on its part – not attacks on Ukraine's energy infrastructure or attempts to cut people off from power and heat, but real steps toward stopping the bloodshed," he wrote.
The prime minister also spoke with his Swedish counterpart Ulf Kristersson on Tuesday about Ukraine.
A spokesperson said: "They underlined the importance of ensuring Ukraine has the long-term security assurances and continued international support it needs to secure a just and lasting peace."
