WASHINGTON (AP) — Four U.S. military personnel investigating potential evacuation routes in Libya were taken into custody at a checkpoint and then detained briefly by the Libyan government before being released, U.S. officials said Friday night.

These four military personnel were operating in an area near the coastal city of Sabratha in northwestern Libya as part of security preparedness efforts when they were taken into custody, State Department spokeswoman Jen Psaki said in a statement. Sabathra, about 40 miles west of Tripoli, is a popular tourist area with its ancient Roman ruins.