Al Qaeda chief Ayman Al-Zawahiri has died in Afghanistan likely of natural causes, Arab News quoting several sources in Afghanistan and Pakistan reported on Friday.

The report quoted at least four security sources in Pakistan and Afghanistan to confirm Zawahiri’s death, adding that two of them said he had died. However, they spoke off the record as they were not authorised to speak to the media.

Zawahiri, 69, last appeared in a video message on the anniversary of 9/11 attacks in the United States this year, the report stated.

Al Qaeda, according to a UN report on the activities of the terrorist groups from around the world issued in July, was covertly active in 12 Afghan provinces and its leader Zawahiri remained based in Afghanistan. The UN had estimated a total number of al Qaeda fighters in Afghanistan between 400 and 600.

If confirmed, the development could potentially create a deep leadership vacuum within al Qaeda as at least two senior commanders who would have been in line to replace him have also been killed recently.

Last week, the New York Times reported that al Qaeda’s second-in-command — accused of helping to mastermind the 1998 bombings of two US embassies in Africa — was killed in Iran in August by Israeli operatives acting at the behest of the United States.

Abdullah Ahmed Abdullah, who went by the nom de guerre Abu Muhammad al-Masri, was gunned down by two men on a motorcycle in the streets of Tehran on August 7, the Times reported, citing intelligence officials.

The killing of Masri, who was seen as a likely successor to Zawahiri, was kept secret until now, the newspaper reported.

In October, Afghan security forces killed Abu Muhsin al-Masri, another person on the FBI’s terrorist list, while the Afghan government this month announced that it had killed yet another senior al Qaeda commander.