Presidents of Russia, France and Ukraine, Vladimir Putin, Francois Hollande and Petro Poroshenko, and German Chancellor Angela Merkel had a telephone conversation on Sunday evening to discuss the implementation of the complex of measures on peace settlement in southeastern Ukraine signed by the Contact Group earlier in the week, the Kremlin press service said.
The four leaders also discussed the difficult situation around the town of Debaltsevo and the role of the mission of the Organization for Security and Cooperation in Europe (OSCE) in controlling the observance of the ceasefire regime.
An agreement on ceasefire in Donbass came into force overnight to Sunday.
"Special emphasis was made on the necessity to strictly observe the ceasefire regime by both conflicting parties and to begin pulling out heavy weapons," the press service said.
Apart from that, the leaders agreed "parameters of further joint efforts in the context of promoting the implementation of the Minsk agreements," the press service said.