An international mediator on Wednesday said Ukraine's warring sides had agreed to withdraw heavy weapons from the volatile frontline by February 20 in line with a tattered peace plan.

Martin Sajdik, the lead negotiator from the Organization for Security and Cooperation in Europe (OSCE) on the crisis, said Ukraine, Russia and the eastern rebels agreed to the move after a fresh round of talks in Minsk, Russian and Belarussian news agencies reported.

The agreement comes after a surge in violence earlier this month saw several dozen people left dead around the flashpoint town of Avdiivka and both sides shift heavy weaponry forward.

Under the Minsk plan -- agreed in the Belarussian capital in 2015 -- the warring parties are meant to withdraw their big guns to create a buffer zone along the frontline.

The Minsk agreement has been repeatedly violated by both sides as no progress has been made towards a political resolution of the conflict.

The war in eastern Ukraine has cost some 10,000 lives since 2014, with Kiev and the West accusing Russia of arming rebels and pouring its troops over the border.