Al Qaeda's Yemeni branch said its head Nasser al-Wuhayshi, a former associate of Osama bin Laden, was killed in a US bombing, according to an online statement posted by the militant group on Tuesday.

Wuhayshi's death is a major blow to Al Qaeda in the Arabian Peninsula (AQAP), the terror network's most active branch that had claimed the attack on French satirical magazine Charlie Hebdo and plotted against international airlines.

"We in Al-Qaeda in the Arabian Peninsula mourn to our Muslim nation ... that Abu Baseer Nasser bin Abdul Karim al-Wuhayshi, God rest his soul, passed away in an American strike which targeted him along with two of his mujahideen brothers, may God rest their souls," Khaled Batarfi, a senior member of AQAP, said.

The group has appointed its former military chief Qassim al-Raymi as his replacement, Batarfi added.

American news network CNN reported that Wuhayshi was killed in a suspected drone strike on Friday in the Hadramout region in eastern Yemen.

The US was assessing reports of his death, a US official told Reuters news agency, speaking on condition of anonymity and declining to comment on any possible US involvement.

The US military was not involved in any strike, a second official said. It was unclear whether a strike may have been carried out by the CIA.

The SITE Intelligence Group, which tracks social media postings by Islamist groups, translated a series of messages by AQAP sympathisers that said Wuhayshi had died.

"Nasser al-Wuhayshi, may God accept him," one supporter identified as Abu Gandi wrote on Twitter under the hash-tag "Martyrdom of Abu Baseer al-Wuhayshi".

‘Blow to the core’

Wuhayshi, according to Gregory Johnson, author of a book on AQAP, was born in southern Yemen and travelled to Afghanistan for the first time in 1998 to join al Qaeda.

There, he met bin Laden and acted as his aide-de-camp until 2001, when the group was scattered after the US-led invasion of Afghanistan that followed the September 11 attacks on the US.

He became head of AQAP in 2009, several years after a daring prison break in Yemen.

In January, AQAP claimed responsibility for the attack on the French satirical newspaper Charlie Hebdo, saying it was ordered in response to insults to the Prophet Mohammed.

US Congressman Adam Schiff, a senior member of the House intelligence committee, said Wuhayshi’s death “would be a significant blow to the core of the terrorist organisation and its most dangerous franchise”.

AQAP’s master bomb-maker, Ibrahim Hassan al-Asiri, is believed to still be alive. He is thought to have designed bombs that were slipped past security and placed on three separate American-bound airplanes, although none of them exploded.

The statement on Wuhayshi’s death came just two days after the recognised Libyan government reported that al Qaeda-linked veteran militant Mokhtar Belmokhtar was killed in a US air strike in Libya on Sunday.

US officials have said Belmokhtar was indeed targeted in the air strike, but have been unable to confirm his death.

(FRANCE 24 with REUTERS, AP)