Ukraine's President Pyotr Poroshenko and U.S. Vice President Joseph Biden had a telephone conversation on Monday, in which they discussed the situation in much-troubled war-torn Eastern Ukraine, the presidential press service said.
The two men noted "a departure from the implementation of the Minsk accords (reached in September 2014 - TASS)," the report said.
They said this led to a further escalation of tensions.
Poroshenko and Biden also discussed the latter man's forthcoming visit to Ukraine that has been scheduled for November 21.