BRUSSELS — NATO's top military commander said on Sunday that Russia had a large force on Ukraine's eastern border and said he was worried it could pose a threat to Moldova's separatist Transdniestria region.

"The (Russian) force that is at the Ukrainian border now to the east is very, very sizable and very, very ready," NATO's Supreme Allied Commander Europe, U.S. Air Force General Philip Breedlove, told an event held by the German Marshall Fund think tank.

He said NATO was very concerned about the threat to Transdniestria. "There is absolutely sufficient (Russian) force postured on the eastern border of Ukraine to run to Transdniestria if the decision was made to do that and that is very worrisome."

"Russia is acting much more like an adversary than a partner," he said.