Hours after meeting Ukraine's head of state Petro Poroshenko, German Chancellor Angela Merkel and French President Francois Hollande are set to hold talks with Russian President Vladimir Putin in Moscow.

The meeting is aimed at finding a solution to renewed tensions in the east of Ukraine, with the two European leaders determined to discuss a peace plan tabled during the meeting with Poroshenko.

No specific information has been released about the peace plan, but according to Der Spiegel magazine President Hollande has said the proposal is respectful of Ukraine's territorial integrity.

Reports of the Sueddeutsche Zeiting, however, suggest the plan includes wide-reaching autonomy for pro-Russian rebels.

After the meeting President Poroshenko has assesed positively talks with the two leaders, adding adding they "give hope" for an effective truce to come into force.

An agreement Kiev struck with Donbass rebels in September has been failing since, with the exception of a few brief periods of a relative ceasefire.

The Donbass region in Eastern Ukraine has been torn by unrest since pro-Russian rebels seized last spring control of Donetsk and Luhansk and adjacent territories, proclaiming "People's Republics" and refusing to recognize the central government in Kiev.

Fierce fighting over the past ten months has claimed the lives of more than 5400 people, according to UN estimates.

The latest diplomatic developments also include a visit of US Secretary of State John Kerry to Kiev, where he again accused Russia of helping aggression in Ukraine.

Moscow for its part reacted on Thursday to a prospective Washington decision to start supplying Ukraine with weapons, with the Foreign Ministry quoted by the BBC as saying such a move would "inflict colossal damage to Russian-American relations."

Thursday's events come against the background of Poroshenko's move to sign a new law on mobilization in Ukraine which raises to 27 maximum age at which a person could be called up to carry out their army service. Partial mobilization has already begun, with a fourth stage announced on January 20. In Poroshenko's owrds, as many as 73 000 people have been summoned so far.