A senior Islamist militant who ordered a deadly attack on an Algerian gas plant two years ago has been killed in a US air strike, Libyan officials say.

Mokhtar Belmokhtar and other fighters were killed in the operation in the eastern city of Ajdabiya, a statement from Libya's government said.

However, there have been several false reports of his death in the past.

The Pentagon said it had targeted a "mid-level" al-Qaeda operative, giving few details.

It said Saturday's operation had been successful but did not name the target, saying officials were still assessing it.

Notoriety

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 gained notoriety with the attack on the In Amenas gas plant in Algeria in 2013, when about 800 people were taken hostage and 38 killed.

The US has filed terror charges against him and officials said they believed he remained a threat to Western interests.

Libya said the strike came after consultation with the US.

The country has been in chaos since the ousting of Muammar Gaddafi in 2011.

Libya's internationally recognised parliament is operating in exile in the eastern port of Tobruk.

A rival parliament, the Islamist-dominated General National Congress, is nearly 1,000km (620 miles) to the west in Tripoli.

Rival militia have been battling to fill the power vacuum, with Islamic State militants battling other Islamists in the east.

Profile: Mokhtar Belmokhtar

• Known as "the One-Eyed", as he often wore an eye patch, also as "Mr Marlboro", as he used cigarette smuggling to finance his jihad
• Fought against Soviet Forces in Afghanistan in the late 1980s
• A former leading figure in al-Qaeda in the Islamic Maghreb (AQIM), but left after falling out with its leaders
• Went on to lead the Islamist militia group al-Murabitoun, which has attacked local and international forces in Mali