Leaders of Russia, Germany and France urged Ukrainian President Petro Poroshenko to extend the ceasefire that will expire Monday in a teleconference held Sunday, the Kremlin press service said.

"The leaders stressed the necessity to make such contacts regular. They called on Poroshenko to extend the ceasefire regime for a longer period," it said.

Russian President Vladimir Putin, German Chancellor Angela Merkel and French President Francois Hollande also hailed the release of observers of the Organization for Security and Cooperation in Europe mission in Ukraine.

Putin "emphasized the necessity to urgently send relief aid" to southeastern Ukraine as the humanitarian situation was "severe," Interfax news agency quoted the press service as saying.

Noting the Ukrainian government has been honoring the ceasefire commitment, Poroshenko accused the separatists in southeastern part of the country of violating the agreement.

The leaders also discussed issues related to Ukraine's signing of the association agreement with the European Union Friday in the teleconference.