Spokesperson of the US Department of Defence John F. Kirby said, "there's been an unusual buildup of Russian military activity near Ukraine in the last several days." "We continue to consult with allies and partners on the issue," he told reporters.
"We continue to monitor this closely. Any escalatory or aggressive actions by Russia would be of great concern to the United States. We would urge Russia to be more clear about its intentions," he added.
Meanwhile, State Department Principal Deputy Spokesperson Jalina Porter said the US made clear in the past that any escalatory or any aggressive type of actions would be of great concern to United States.
"We're certainly concerned with any public reports of unusual Russian military activity near the Ukraine - excuse me, near Ukraine," she added.