WASHINGTON (CNN) -- Pirates off the eastern coast of Africa fired on U.S. sailors Saturday as they tried to reach the lifeboat where an American captain is being held, a U.S. official familiar with the situation told CNN. The gunfire forced the sailors, who did not return fire, to turn back, the official said. The incident took place some 12 hours ago as the guided missile destroyer USS Bainbridge sent a small team toward the lifeboat, said the official.