Russia continues to provide support to the separatists in eastern Ukraine by providing military leadership and training, U.S. Ambassador in Ukraine Geoffrey Pyatt has said.

"Russia has command and control centers in eastern Ukraine to coordinate military operations there," Pyatt tweeted on Tuesday.

"We know Russia has established training areas in eastern Ukraine to train separatist fighters in gunnery and artillery firing," he said.

Pyatt added that Russia continues to station advanced surface-to-air missile systems near the frontline in violation of the Minsk agreements.