Ukrainian President Petro Poroshenko, French President Francois Hollande and German Chancellor Angela Merkel, in a conference call on Saturday, expressed anxiety over the situation in Debaltseve, eastern Ukraine, and urged strict compliance by everyone with Thursday's peace deal.

They "pointed out that now the implementation of the latest agreement reached in Minsk is the key objective, and that all the parties, including Russia, must fulfill their commitments, primarily the commitment to cease fire as from midnight today," the Ukrainian president's office said in a statement.

"They also expressed anxiety over the Debaltseve situation and came to an agreement to monitor it closely," the office said.