A Syrian rebel commander who fought alongside al Qaeda founder Osama bin Laden and was close to its current chief, Ayman al-Zawahiri, was killed by a suicide attack on Sunday, intensifying infighting between rival Islamist fighters.

The Observatory for Human Rights in Syria said Abu Khaled al-Soury (also known as Abu Omair al-Shamy), a commander of the Salafi group Ahrar al-Sham, was killed along with six comrades by al Qaeda splinter group the Islamic State of Iraq and the Levant (ISIL).

Ahrar al-Sham is one of the main rebel groups in the Islamic Front alliance, the biggest rebel alliance in Syria, which has been locked in battle with the ISIL.

Al-Soury’s death will fuel rebel infighting that has killed hundreds of fighters in recent months, rebels said, distracting from their common purpose of ousting President Bashar al-Assad.

A friend of bin Laden

Two rebels told Reuters that five ISIL members had entered Ahrar al-Sham headquarters in Aleppo, where it engaged fighters and one ISIL jihadist blew himself up.

“Sheikh Abu Khaled was an important jihadi figure, he fought the Americans in Iraq and in Afghanistan. They (ISIL) gave the Americans a present, a free gift, by killing him,” said a Syrian rebel close to the group. “He was a very important commander, he is a close friend of Sheikh Ayman (al-Zawahiri) and he knew Sheikh Bin Laden.”

Syrian rebels mourning al-Soury posted his picture on social media accounts, while at least one fighter called for revenge, saying that ISIL had “pushed it too far this time”.

Al-Soury was born in Aleppo in 1963. A senior rebel source said he had been based in Afghanistan but was sent by Zawahiri to Syria a few months ago on a mission to try to end the infighting.

Sources said that by killing al-Soury, ISIL had taken the war between jihadi factions to a new level. The decision to kill him must have been taken by the high command of ISIL, sources said, most probably its leader Abu Bakr al-Baghdadi, who fell out with Zawahiri last year.

ISIL, which grew from al Qaeda’s onetime Iraqi affiliate, is facing a widespread backlash from an array of rebel brigades angered by its abuses against civilians and rival opposition fighters.

Several Islamist rebel factions joined forces in January for an offensive to try to push their ISIL former allies out of rebel-held regions in northern and eastern Syria.

Sources close to Ahrar al-Sham said that al-Soury had rejected the infighting and opposed fighting ISIL after Zawahiri had appointed him to mediate between jihadi groups.

(FRANCE 24 with REUTERS, AFP)