By Barbara Starr
Ukrainian military forces have moved into defensive positions around bases and weapons depots in the past few hours, according to a U.S. defense official familiar with the latest intelligence.
The move is seen by the United States as an effort to ensure the military's facilities remain secure.
So far, the move appears to mainly involve Ukraine military personnel, with no widespread movement of armored vehicles.
All of that is leading to the preliminary U.S. assessment that the move is defensive.
"We are encouraged the Ukraine military has not been brought into this crisis and we urge them to remain on the sidelines," said Col. Steve Warren, Pentagon spokesman.
If the military forces were to enter the fighting "that would have consequences for our defense relationship," he added.
The Pentagon provides Ukraine with military education at U.S. training centers and schools, grants to purchase U.S.-made equipment for units/ships designated for NATO operations, and other seminars and training, Warren said.
The California National Guard is partners with Ukraine through the State Partnership Program, and conducts military seminars each year.
The U.S. and Ukrainian militaries have operated together in Iraq and Afghanistan, and conduct two exercises annually in Ukraine. One is a ground forces peacekeeping exercise and the other is a naval exercise.