German Chancellor Angela Merkel and French President Emmanuel Macron are urging both sides in eastern Ukraine to live up to cease-fire agreements amid a recent upswing in clashes between Russia-backed separatists and Ukrainian forces.

The statement comes a day after U.S. officials said they would begin sending lethal weapons, including anti-tank missiles, to equip Ukrainian troops.

Merkel and Macron issued a joint statement Saturday urging combatants to observe the Minsk agreements aimed at defusing the conflict. Those provisions include the withdrawal of heavy weapons such as tanks and rocket launchers from the front-line area and an exchange of prisoners.

The two leaders also urged the return of Russian military officers to a joint coordination center that plays a role in monitoring the cease-fire. Russian President Vladimir Putin and Merkel discussed the issue Thursday. Putin said the Russian move had been prompted by "restrictions and provocations" by Ukrainian authorities that made it hard for Russian officers to perform their duties.

"There is no alternative to an exclusively peaceful settlement of the conflict," German Chancellor Angela Merkel and French President Emmanuel Macron said in a statement issued by the Elysee, referring to "the recent unacceptable increase of ceasefire violations".

The conflict in the former Soviet republic has killed more than 10,000 people since April 2014.

Merkel and Macron did not comment in their statement on the U.S. decision to supply weapons to Ukraine.

Violence has frequently broken out and UNICEF this month warned that hundreds of thousands of children are at imminent risk of being hit by mines and other explosive weapons in the war-torn east.