By Barbara Starr, CNN Pentagon Correspondent
updated 9:32 PM EST, Fri December 27, 2013
(CNN) -- Four U.S. military personnel are being held by the Libyan government, a senior U.S. Defense Department official told CNN on Friday.
The four are believed to have been detained by the ministry of the interior, said the official, who spoke on condition of anonymity.
It was not immediately known why the American personnel were being held. "We are seeking to further ascertain the facts and ensure their release," said the official.
The four were in Libya "augmenting security at the U.S. Embassy in Tripoli," the official said.