The leaders of France, Germany, Russia and Ukraine called Monday for a peace deal aimed at ending the separatist war in eastern Ukraine to be implemented "as quickly as possible", as fresh clashes erupted.

The office of France's President Francois Hollande said in a statement the leaders spoke over the phone and "recalled their commitment to the Minsk peace accords and their determination to do everything to ensure they are implemented in full as quickly as possible".

The Minsk accords, signed in February 2015 with French and German mediation and in the presence of Russian President Vladimir Putin, calls for a ceasefire along with a range of political, economic and social measures to end the conflict in eastern Ukraine.

The call comes as a Ukrainian soldier was killed and three others injured in a mortar attack by pro-Russian insurgents in the country's east, where violence has persisted since the peace treaty.

Ukrainian leader Petro Porochenko and German Chancellor Angela Merkel along with France's Hollande and Russia's Putin also called for an immediate cessation of hostilities.

"They stressed the importance of implementing all necessary measures to consolidate the ceasefire in eastern Ukraine, starting with the withdrawal of weapons and planning the disengagement of armed forces," the statement said.

Kiev and the West have accused Russia of buttressing the rebels and sending in regular troops across the border, claims Moscow has repeatedly denied.

Ukrainian Defence Minister Stepan Poltorak said last month that it could take years to end the conflict, which has claimed more than 9,300 lives since it erupted in April 2014.

Earlier this month, France and Germany held a round of talks with Kiev and Moscow as part of efforts to try to seek a lasting peace deal but no consensus was reached over elections in the separatist regions of eastern Ukraine.