Abu Khalid al Suri, a founder of the Islamic rebel group Ahrar al Sham, was killed in an attack by rival Islamic rebels Sunday in Aleppo, the Wall Street Journal reported.
Ahrar al Sham said Suri had been asked by al-Qaida leader Ayman al Zawahiri to help settle differences between the Nusra Front, al-Qaida's designated representative in Syria, and the Islamic State of Iraq and al-Sham, which al-Qaida recently disavowed.
Ahrar al Sham blamed ISIS for the deadly bombing, but ISIS denied the accusation.
Extremist rebels in Syria have been splintering, which is indicative of a broader split within al-Qaida's global organization, an expert told the Journal. The more hard-line factions have complained that al-Qaida has become less strident since Zawahiri took control after Osama bin Laden's death in 2011.
"At this point, it's a competition between al-Qaida and ISIS about who will become the beacon of the global jihadist movement and Syria is at the pinnacle of this," said Aaron Zelin, a fellow at the Washington Institute focusing on jihadist movements.