"They're greatly concerned about being contained," the director of national intelligence, James Clapper, told the Senate Armed Services Committee.
Clapper said that Russia fears the installation of a missile defense network in Europe could negate the threat posed to the West by its nuclear arsenal.
"I think the Russians fundamentally are paranoid about -- about NATO," he said.
"So, a lot of these aggressive things that the Russians are doing, for a number of reasons -- great power status, to create the image of being co-equal with the United States etc. -- I think could probably -- could possibly -- go on, and we could be into another Cold War-like spiral here," he added.
