The presence of the Russian Armed Forces in the east of Ukraine has been confirmed and there is no doubt about it, the U.S.' Special Representative for Ukraine Negotiations, Kurt Volker, said.

The statement that Russia controls and manages the military forces in Ukraine's east presently does not raise any doubts, he said in an interview with the Russian newspaper Gazeta.ru published on Friday.

Volker explained that there is a lot of public information confirming this: photographs, including satellite images, information from social networks, and reports on interrogation of Russian servicemen who were taken captive.

The envoy said he doesn't think the U.S. should provide any evidence to support this.