CNN reported the chopper carrying Sens. Joseph Biden, D-Del.; John Kerry, D-Mass.; and Chuck Hagel, R-Neb., was forced down in a snowstorm in the mountains. Kerry spokesman David Wade told CNN the senators, all members of the Senate Foreign Relations Committee, were then taken by convoy to Bagram Air Base, from where they left for Ankara, Turkey.

"They're fine, it was just an unscheduled landing," Biden spokeswoman Elizabeth Alexander told The Hill.

The three are on a trip to Pakistan, Afghanistan, India and Turkey. They were observers for Pakistan's elections and also visited U.S. troops in Afghanistan before continuing on to Turkey and India to talk with government leaders.

The Pentagon said the incident occurred about 8:30 a.m. EST.