Russian President Vladimir Putin, French President Emmanuel Macron, German Chancellor Angela Merkel and Ukrainian President Volodymyr Zelensky (L to R) attend "Normandy four summit" in Paris, France, Dec. 9, 2019. (Xinhua/Gao Jing)

Russian President Vladimir Putin and German Chancellor Angela Merkel on Monday discussed by telephone the ceasefire reached in Ukraine, Russian gas supplies to Europe and the Libyan crisis.

The two leaders gave a positive assessment of the ceasefire reached in Ukraine's eastern Donbass region during the "Normandy Four" summit of Russian, Ukrainian, German and French leaders in Paris last week, said a Kremlin press release.

Putin and Merkel also discussed the delivery of Russian natural gas through Ukraine to Europe after the current contract expires on Jan. 1, 2020 and the implementation of the Nord Stream-2 pipeline that will pump Russian gas to Europe under the Baltic Sea.

Regarding the Libyan crisis, the importance of preventing a further aggravation of the situation and the need for resuming peaceful dialogue were noted, the Kremlin said.

Putin reaffirmed Russia's readiness to continue to help facilitate mediation efforts in Libya by Germany and the United Nations.