U.S. Undersecretary of State Victoria Nuland did not make assumptions about how long the Russian Federation can afford to keep a large grouping of forces near Ukraine.

"I am going to let the Russians speak for themselves," she said, answering a question at a State Department briefing about "how long you think Russia can financially back the placement of troops along the Russia-Ukrainian border."

Nuland also said the transfer of a large group of forces to the border with Ukraine was not a cheap operation.

"These kind of deployments, hundred thousand troops out of barracks and on the Ukrainian border are extremely expensive, as is the deployment of this kind of weaponry in the cold winter," she said.