Ukrainian President Petro Poroshenko and U.S. Vice President Joe Biden had a phone call and discussed security at the administrative border with Crimea and in Donbas.

"The leaders pointed out the importance of political and diplomatic efforts to de-occupy Crimea," the press service of the Ukrainian head of state reported on the official website late on Friday.

Biden also said that the United States continues to reject the occupation and annexation of Crimea.