"The President also reaffirmed our support for German- and French-led efforts to negotiate a peaceful settlement to the conflict in Ukraine on the basis of the Minsk agreements," the readout of Trump's call with Merkel said.

They addressed other "issues of mutual concern." "The leaders discussed the conflicts in Syria and Yemen and the urgent security challenge posed by North Korea," the readout said.

Read alsoU.S. not to lift sanctions against Russia until Minsk accords implemented – Department of StateAs UNIAN reported earlier, U.S. Secretary of State Rex Tillerson on Sunday phoned Poroshenko to discuss his recent trip to Moscow and his message to the Russian leadership.

"Secretary Tillerson reiterated the United States' firm commitment to Ukraine's sovereignty and territorial integrity and confirmed that sanctions will remain in place until Russia returns control of the Crimean peninsula to Ukraine and fully implements its commitments in the Minsk agreements," the U.S. Department of State said.