WASHINGTON (Reuters) - The U.S. Air Force on Tuesday flew some American personnel out of Sanaa, Yemen, the Pentagon said, as the United States told its citizens to leave the country and ordered the evacuation of non-essential government staff because of a terror threat.

"In response to a request from the U.S. State Department, early this morning the U.S. Air Force transported personnel out of Sanaa, Yemen, as part of a reduction in emergency personnel," Pentagon spokesman George Little said in a statement.

He did not specify which types of personnel were involved or where they were taken.

"The U.S. Department of Defense continues to have personnel on the ground in Yemen to support the U.S. State Department and monitor the security situation," the statement said.

(Reporting by Phil Stewart; Editing by Bill Trott)