US air force bombers have attacked Islamic State military camps in Libya.
The attack by the B-2 planes was aimed at eliminating extremists who had escaped the former IS stronghold of Sirte, a defence official said.
The official said the camps were located about 28 miles south-west of the central coastal city of Sirte.
The strikes were carried out overnight and were authorised by President Barack Obama, marking perhaps the final use of military force by a wartime president who intervened in Libya in 2011 as part of a coalition that ultimately toppled dictator Muammar Gaddafi.
The defence official said the latest strikes were aimed at hitting IS militants who had escaped from Sirte after US strikes largely eliminated the group's presence in the coastal city in December.
At the time, Pentagon officials said they would further support counter-IS efforts if asked by Libya's provisional government.
Libya fell into chaos following Gaddafi's ousting and death. The country remains divided between east and west, with no effective government and a multitude of rival factions and militias.