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, Reuters reports.
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 members of the Islamic State of Iraq and the Levant (ISIS).
The Observatory said al-Soury had fought in Iraq and Afghanistan, according to Reuters.
Al-Soury's death will fuel the infighting among jihadists fighting President Bashar Al-Assad, a violent rivalry that has killed hundreds of fighters in recent months, rebels said.
Two rebels told Reuters that five ISIS members had entered Ahrar al-Sham headquarters in Aleppo, engaged its fighters and then one ISIS fighter 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," a Syrian rebel close to the group told the news agency.
The civil war in Syria has attracted many jihadist rebel groups, such as the Al-Nusra Front and ISIS. In addition to fighting Assad’s forces, these groups have been fighting the more moderate rebel groups in what has turned into a second war.
These Al-Qaeda-linked groups have been heading to war-torn Syria from many other countries since fighting broke out in 2011.
In recent weeks, the infighting between rebels has worsened, as three powerful rebel alliances – among them Islamist groups - have teamed up to fight ISIS, which they have warned is even worse than Assad’s regime.
Syrian rebels mourning al-Soury posted his picture on social media accounts. A fighter called for revenge, saying that ISIS 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, reported Reuters.
Sources said that, by killing al-Soury, ISIs had taken the war between jihadist factions to a new level, and that the decision to kill him must have been taken by the high command of ISIS, most probably its leader Abu Bakr al-Baghdadi, who fell out last year with Zawahiri and the leader of the Al-Nusra Front.