Britain's Prime Minister Keir Starmer co-chairs the Coalition of the Willing videoconference call with European leaders on Ukraine, ahead of the expected meeting of U.S. President Donald Trump and Russia's President Vladimir Putin in Alaska, in London, Britain, August 13, 2025. REUTERS/Jack Taylor/Pool
Britain's Prime Minister Keir Starmer co-chairs the Coalition of the Willing videoconference call with European leaders on Ukraine, ahead of the expected meeting of U.S. President Donald Trump and Russia's President Vladimir Putin in Alaska, in London, Britain, August 13, 2025. REUTERS/Jack Taylor/Pool
Britain's Prime Minister Keir Starmer co-chairs the Coalition of the Willing videoconference call with European leaders on Ukraine, ahead of the expected meeting of U.S. President Donald Trump and Russia's President Vladimir Putin in Alaska, in London, Britain, August 13, 2025. REUTERS/Jack Taylor/Pool

LONDON (Reuters) -British Prime Minister Keir Starmer told U.S. President Donald Trump and European leaders that support for Ukraine was unwavering and that there should be robust security guarantees as part of any peace deal with Russia.

"The Prime Minister was clear that our support for Ukraine is unwavering - international borders must not be changed by force and Ukraine must have robust and credible security guarantees to defend its territorial integrity as part of any deal," a readout of a call from Starmer's Downing Street office said.

The call, which also included Ukrainian President Volodymyr Zelenskiy and the leaders of France, Germany, Italy, Poland, Finland, NATO and the European Union, comes ahead of a meeting between Trump and Russian President Vladimir Putin in Alaska on Friday.

(Reporting by William James, writing by Sachin Ravikumar, editing by Catarina Demony)