French President Francois Hollande and German Chancellor Angela Merkel are due to hold talks in Moscow to try to end escalating fighting in east Ukraine, the BBC reports.
Their meeting with President Vladimir Putin follows urgent talks in Kiev, where a new peace plan was presented.
US Secretary of State John Kerry, who was also in Kiev, said the US wanted a diplomatic solution, but would not close its eyes to Russian aggression.
President Hollande and Mrs Merkel will meet President Putin in Moscow later on Friday to discuss new peace proposals.
On Thursday, the two leaders examined the plan with Ukrainian President Petro Poroshenko, without releasing any details.
Mr Poroshenko said in a statement that the meeting with Ms Merkel and Mr Hollande “give hopes… for a ceasefire”.
Ahead of the Kiev talks, Mr Hollande said he and Mrs Merkel would present a new peace proposal based on the “territorial integrity” of Ukraine, which could be “acceptable to all”.