NATO said on Monday it was putting forces on standby and reinforcing eastern Europe with more ships and fighter jets, in what Russia denounced as Western "hysteria" in response to its buildup of troops on the Ukraine border.
The U.S. Department of Defense in Washington said about 8,500 American troops were put on heightened alert and were awaiting orders to deploy to the region, should Russia invade Ukraine.
Tensions are high after Russia massed an estimated 100,000 troops in reach of its neighbor's border, surrounding Ukraine with forces from the north, east and south.