The leaders of Russia, Germany and France have agreed during late-night talks in Moscow to draw up a plan to end fighting in Ukraine as rebels wage a deadly offensive in the country's east, officials said.
A spokesman for Russian President Vladimir Putin said that more than four hours of talks that wrapped up early on Saturday saw the leaders agree on the drafting of a blueprint that would also include proposals from Ukraine's Petro Poroshenko.
No details of the plan were released, but Kremlin spokesman Dmitry Peskov told reporters the talks had been "substantial and constructive", adding that German Chancellor Angela Merkel and French President Francois Hollande left swiftly afterwards.
"Work is under way to prepare the text of a possible joint document to implement the Minsk agreements," said Peskov, referring to a widely flouted truce from September.
A French official also called the talks "constructive and substantial" and said work was being done to pull together a document aimed at implementing the September truce.
Putin, Merkel and Hollande, who did not address the media after the meeting, are to discuss the effort with Ukrainian President Poroshenko by telephone on Sunday.
The European pair's talks with the Russian leader were seen as an attempt to prevent the 10-month conflict in east Ukraine from spiralling out of control as Washington considers supplying weapons to Kiev.
The visit was Merkel's first to Moscow since the start of the Ukraine crisis while Hollande had made a brief stopover in December.
Ahead of the talks, Merkel played down hopes of a rapid end to the fighting that has claimed more than 5,300 lives since April, according to the UN.
But she added: "We have to put an end to this bloodbath and implement the Minsk agreements."
Merkel and Hollande first flew to Kiev on Thursday for discussions, when US Secretary of State John Kerry also visited the Ukrainian capital.
Kerry is set to meet Russia's top diplomat Sergei Lavrov at a security conference in Munich on Saturday, with the high-level diplomacy seeking to resolve the worst East-West crisis since the end of the Cold War.
'Russia cannot redraw the map'
On Friday, US Vice President Joe Biden said Ukraine was battling for survival in the face of escalating Russian military involvement.
"We, the US and Europe as a whole, have to stand with Ukraine at this moment," Biden said in Brussels.
"Russia cannot be allowed to redraw the map of Europe.
"President Putin continues to call for new peace plans as his troops roll through the Ukrainian countryside, and he absolutely ignores every agreement his country has signed in the past."
The West and Kiev accuse the Kremlin of sending troops and sophisticated weapons across the border to bolster separatists in Ukraine. Moscow has insisted it is not a party to the conflict.
Observers have warned that if the US gets involved militarily the regional conflict could reach a dangerous new stage and become a proxy war between Russia and the West.
Russia is already under heavy Western sanctions over its alleged actions in Ukraine, and European Union officials said on Thursday that the bloc would blacklist more Russian individuals.
The sanctions already in place, combined with tumbling oil prices, have dealt a blow to Russia's economy but have failed to force Putin to change tack over Ukraine.
Ahead of the talks, Hollande said a ceasefire should be "the first step" on the path to a comprehensive settlement. Kerry voiced support for what he called a "helpful" Franco-German plan.
"President Putin can make the choices that could end this war," he said.