Washington, March 14 : US President Donald Trump on Friday said that he had appealed to Russia's President Vladimir Putin that the lives of thousands of Ukrainian troops "completely surrounded" by the Russian military be "spared".

Trump wrote on Truth Social, his social media platform, that he made this appeal on a phone call with Putin on Thursday, which he described as "good and productive".

Trump did not specify, but he was referring to the Russian military's advance on a Russian territory in the Kursk region which had been seized by Ukraine.

The Russian President visited that area on Thursday to mark the progress by the military there.

"We had very good and productive discussions with President Vladimir Putin of Russia yesterday, and there is a very good chance that this horrible, bloody war can finally come to an end ' BUT, AT THIS VERY MOMENT, THOUSANDS OF UKRAINIAN TROOPS ARE COMPLETELY SURROUNDED BY THE RUSSIAN MILITARY, AND IN A VERY BAD AND VULNERABLE POSITION," Trump wrote in the post.

"I have strongly requested President Putin that their lives be spared. This would be a horrible massacre, one not seen since World War II."

Ukraine's top commander denied Ukrainian troops were being encircled in Kursk, as reported by Reuters, and insisted they were adopting better defensive positions.

President Trump's envoy Steve Witkoff reached Moscow for talks on Thursday, the day the Russian leader announced his in-principle agreement to the ceasefire plan offered. But he had made clear his conditions will have to be met before he signed off on it, chiefly that Ukraine must not be allowed to use the pause to mobilise troops and not be supplied with weapons.

A ceasefire of 30 days was proposed by the US and Ukraine accepted it at a meeting between US Secretary of State Marco Rubio and National Security Adviser Mike Waltz with Ukrainian officials in Jeddah, Saudi Arabia.

/IANS