British Prime Minister David Cameron and Ukrainian President Petro Poroshenko on Sunday discussed in a phone call the situation in eastern Ukraine following a newly adopted ceasefire.

"They agreed on the importance of both sides respecting the ceasefire," a Downing Street spokesperson said in a statement.

The statement noted that both leaders expressed "concern" about the situation on the ground.

"While the level of fighting has lessened considerably since the ceasefire came into force at midnight, there have been multiple violations in particular around the town of Debaltseve," it said.

The two leaders also discussed "what role the United Nations Security Council could play in supporting the ceasefire and the agreements reached in Minsk in September 2014 and February 2015."

Russian President Vladimir Putin, Ukrainian President Petro Poroshenko, German Chancellor Angela Merkel and French President Francois Hollande reached a peace agreement on Thursday in Minsk, capital of Belarus.

The accord includes a ceasefire from Feb. 15, withdrawal of heavy weapons from the frontline, election timelines in eastern Ukraine, border control and prisoner exchange.
However, the long-awaited glimmer of hope was overshadowed by the flare-up of hostilities between government troops and pro-independence rebels, sparking international concerns over the full implementation of the peace agreement.