French President Emmanuel Macron on Friday held talks in Paris with his Ukrainian counterpart Volodymyr Zelensky as Russian troops continue to amass on Ukraine's border.
The pair were joined by newly vaccinated German Chancellor Angela Merkel via videolink in a show of Western backing for Kiev.
Mr Zelensky called for a summit with Russian Preisdent Vladimir Putin and a new ceasefire, while France and Germany urged Moscow to withdraw its troops amid fears it was planning an invasion.
The leaders of France and Germany have been mediators in the conflict since 2015 in the so-called Normandy format and have overseen fragile peace.
Mr Putin and Mr Zelensky last met face to face in this format in Paris in December 2019. The meeting was credited with helping to reduce tension in subsequent months.
"I want to get the four of us together to discuss the issue of the security situation in eastern Ukraine and the de-occupation of our territories," Mr Zelensky said at the Ukrainian embassy in Paris after the talks.
He said he hoped a ceasefire could be restored after a meeting of senior advisers from the four countries scheduled for Monday.
Ms Merkel's spokesman said the three leaders had "shared concerns about the build-up of Russian troops".
"They called for the reduction of these troop reinforcements in order to bring about a de-escalation of the situation," he said.
In Moscow, Kremlin spokesman Dmitry Peskov urged the Western leaders to tell Kiev to "decisively stop any provocative actions on the contact line and emphasise the need for an unconditional observance of the ceasefire regime".
In recent weeks, Moscow has amassed tens of thousands of troops along Ukraine's northern and eastern borders, as well as in annexed Crimea.
A bout of clashes in eastern Ukraine effectively ended a ceasefire agreed on last July that ushered in a period of relative calm.
More than 13,000 people have been killed in the fighting, including 28 Ukrainian soldiers since the start of the year compared to 50 in all of 2020.
Ukraine, where a pro-Kremlin president was ousted in a popular uprising in 2014, has made clear its ambition to join Nato, in statements that have riled the Kremlin.
"We cannot stay indefinitely in the EU and Nato waiting room," Mr Zelensky told French daily Le Figaro in an interview ahead of his visit.
"If we belong to the same family, we must live together. We cannot go out together forever, like eternal fiances, we must legalise our relations."
France's Europe Minister Clement Beaune, however, emphasised that supporting Ukraine was not the same as giving it EU membership, "which is not a serious prospect".
The situation in eastern Ukraine comes against the background of escalating tension between Moscow and Washington as new US President Joe Biden seeks a tougher line against Mr Putin.
US and Russia in tit-for-tat diplomat expulsions
The US on Thursday announced sanctions and the expulsion of 10 Russian diplomats in retaliation for what the White House said was the Kremlin's US election interference, a major cyber attack and other hostile activity.
Russia said on Friday it would expel US diplomats and sanction US officials in response, while recommending the US envoy leaves Russia "for consultations".
Meanwhile, both Europe and the US have expressed disgust over the jailing of opposition figure Alexei Navalny in a prison camp after he returned to Russia from Germany, after what the West says was an attempted assassination using the Russian nerve agent Novichok.
Some observers have cast the escalation as an attempt by both Moscow and Kiev to test Mr Biden to see how far he is willing to go to defend Washington's ally and confront Russia.