German Chancellor Angela Merkel has said a bid to resolve the Ukrainian conflict is "uncertain but worth trying", as the French President warned it was "one of the last chances" for peace.
Speaking at a security conference in Munich, Mrs Merkel also said Russia "needs to its bit" in resolving the Ukrainian crisis.
She accused Moscow of showing "territorial disrespect" for its neighbour, and said international law had been violated.
Mrs Merkel told the summit: "We want to shape security on Europe together with Russia not against Russia.
"Russia needs to do its bit in the Ukrainian crisis as well.
"This crisis cannot be resolved by military means."
Her comments come after she and the French President Francois Hollande met Russian leader Vladimir Putin in Moscow, in what was widely seen as a last-ditch attempt to thrash out a deal to end fighting which has claimed the lives of more than 5,300 people.
The Kremlin has described the discussions as "substantial and constructive".
Mrs Merkel said of the peace efforts: "It is uncertain whether it will lead to success, but from my point of view and that of the French President (Francois Hollande) it is definitely worth trying.
"I believe we owe that much to those who are affected in Ukraine."
Mr Hollande told reporters: "I think this is one of the last chances, that's why we took this initiative.
"If we don't manage to find not just a compromise but a lasting peace agreement, we know perfectly well what the scenario will be. It has a name, it's called war."
Clashes between pro-Russian separatists and Ukrainian forces in the east of the country have escalated in recent weeks, despite a peace deal agreed in Minsk last September.
A spokesman for the Ukrainian military said that five soldiers had been killed and 26 wounded in fighting in the last 24 hours alone.
He said separatists had stepped up shelling of government forces and appeared to be amassing for new offensives on the key railway town of Debaltseve and the coastal city of Mariupol.
There are also fears of a growing humanitarian crisis in the war-torn east of the country.
The West accuses Russia of sending troops and weapons across the border although Moscow has consistently denied backing the rebels.
Mrs Merkel and Mr Hollande went to Moscow with a peace proposal discussed during a separate meeting with Ukrainian President Petro Poroshenko on Thursday.
Asked at the Munich Security Conference on Saturday whether he thought the peace proposal could work, Mr Poroshenko replied: "Yes."
Amid a debate in Washington over whether to send weapons to help the Kiev government fight pro-Russian rebels, the German Chancellor argued this would not help end the crisis.
"There is already a large number of weapons in the region and I don't see that this has made a military solution more likely," she said.
Her comments echo those of the British Defence Secretary Michael Fallon who warned providing additional weapons could escalate the conflict.
But NATO's top military commander has said this should not be ruled out.
1/5
-
Gallery: Civilians Flee Besieged Ukrainian Town
A member of the Ukrainian armed forces assists local residents onto a bus to flee fighting in Debaltseve, eastern Ukraine
Two dozen buses escorted civilians out of the town after separatist rebels and government forces agreed a brief truce to allow civilians to be evacuated. Click through for more images ...
