Chancellor Angela Merkel on Tuesday urged Russian President Vladimir Putin to use his influence to rein in separatists in eastern Ukraine

Chancellor Angela Merkel on Tuesday urged Russian President Vladimir Putin to use his influence to rein in separatists in eastern Ukraine, a day after the German leader warned that a peace deal was not being fully implemented.

During a phone call, Merkel "made it clear to President Putin that in order to obtain further progress towards a comprehensive political solution", a ceasefire had to be respected and unfettered access given to observers monitoring the truce.

"Here, Russia must use its influence on the separatists," she said, according to a statement issued by her spokesman.

The conversation came a day after Merkel hosted Ukraine's President Petro Poroshenko for talks, with the Ukrainian leader accusing Russia of continuing to send troops and weapons into his country in violation of a ceasefire deal.

Kiev and Moscow finalized the peace accord brokered by France and Germany in the Belarus capital of Minsk last February, but sporadic clashes still took place on the frontline.

Poroshenko blamed "Russia and its proxies" for the violence, saying they have failed to observe the ceasefire and were responsible for 1,200 shellings in January alone.

He also said observers from the Organisation for Security and Cooperation in Europe (OSCE) were being denied access to the border.

But Putin has repeatedly denied playing any direct role in the war.

More than 9,000 people have been killed and 20,000 injured in the conflict in Ukraine since April 2014, according to the United Nations.