
Mokhtar Belmokhtar and other fighters were killed in the raid by aircraft in the eastern city of Ajdabiya.
The US confirmed that Belmokhtar was targeted, but did not say he had died.
The Pentagon Spokesman, Colonel Steve Warren, described the strike as successful and that officials were still assessing its results.
He said it would “provide more details as appropriate”.
Born in Algeria, Belmokhtar was a former senior figure in Al-Qaeda in the Islamic Maghreb (AQIM), but left to form his own militia.
He was reported to have gained notoriety with the attack on the In Amenas gas plant in Algeria in 2013, when about 800 people were taken hostage and 40 killed, most of whom were foreigners, including six Britons and three Americans.
There have been several false reports concerning Belmokhtar’s death.
In 2013, Belmokhtar was believed to have died fighting in Mali.
He has earned a reputation as one of the most elusive Jihadi leaders in the region.
Since the fall of Muammar Gaddafi in 2011 and Libya’s slide into chaos and fighting between two rival governments, the North African state has seen the rise of Islamic militant groups, who have taken advantage of the turmoil.