WASHINGTON _ Stealth bombers and armed drones attacked two suspected Islamic State desert camps Wednesday night in northern Libya in an expansion of the U.S. air war there, according to the Pentagon.
The attacks were authorized by President Barack Obama two days before he leaves office and are a reminder of the continuing turmoil in the oil-rich nation where a U.S.-led air war helped insurgents overthrow strongman Moammar Gadhafi in 2011.
Islamic State militants in Libya have established what officials say is the group's largest and most powerful affiliate outside its self-declared caliphate in Syria and Iraq, although its area of control has shrunk considerably over the last year.
At least two B-2 bombers launched from Whitman Air Force Base in Missouri bombed the two desert camps about 30 miles southwest of Surt, a port city on the central Mediterranean coast that U.S.-backed Libyan forces recaptured last year from the militants.
U.S. officials said dozens of militants had escaped from Surt to the desert camps.
U.S. officials said aerial surveillance showed fighters carrying weapons, wearing tactical vests and standing in formation before Wednesday's airstrikes.
"While we are still evaluating the results of the strikes, the initial assessment indicates they were successful," Pentagon spokesman Peter Cook said in a statement.
Obama authorized the air raid after a formal request was transmitted from the Western-backed unity government, which is known as the Government of National Accord and headed by Prime Minister Fayez Serraj.
Each U.S. airstrike in Libya, under a military campaign called Operation Odyssey Lightning, must be approved by Gen. Thomas Waldhauser, commander of U.S. Africa Command, which oversees military operations on the continent.
Waldhauser's authority previously was limited to Surt, but Obama expanded the "area of hostilities" in Libya where American forces may operate, according to officials.
The Islamic State took advantage of Libya's political instability in late 2014 by attacking oil fields and installations, hobbling a major source of income for the fledgling government.
It attracted hundreds of recruits from elsewhere in Africa, raising fears that the group would use Libya to launch terrorist attacks in Europe and Africa.
The Pentagon began bombing around Surt in August and positioned the amphibious assault ship Wasp about 20 miles offshore to assist in the operation.
