Russia starting to reinforce positions in eastern Ukraine - U.S. official

The United States believes that Russia has started reinforcing and resupplying its troops in Donbas in eastern Ukraine, a senior U.S. defense official said on Monday.

The United States did not however believe this was the start of a new offensive in the region, the official said, speaking on condition of anonymity.

The official said the United States did not have evidence that any S-300 missile defense system had been destroyed by Russia.