BEIRUT — An extremist group embroiled in infighting with one of the largest Syrian rebel groups pledged allegiance to Al Qaeda-linked militants in Syria Sunday, a move that threatens to deepen divisions in the already disparate insurgency.

The group, Jund al-Aqsa, has been battling the powerful Ahrar al-Sham group in northern Syria for days, after the latter accused it of ambushing its leaders.

Others said the fighting was triggered when the ultraconservative Ahrar al-Sham attacked Jund al-Aqsa group positions in several places.

The infighting killed several Ahrar al-Sham members and stalled an offensive led by Jund al-Aqsa against government troops in the central Hama province.


Scores of Syrian rebel factions rallied behind Ahrar al-Sham, accusing Jund al-Aqsa of espousing extremist ideologies and seeking to dominate other rebel groups. In various statements, rebel factions accused Jund al-Aqsa of serving Islamic State militants, who are at odds with all Syrian insurgents, including the Al Qaeda-linked Fatah al-Sham Front.

On Sunday, Fatah al-Sham Front announced Jund al-Aqsa would join its ranks ‘‘to stop the bloodshed.’’

‘‘It is good news,’’ said Abu Dardaa al-Shami, a Jund al-Aqsa member.

The declaration is expected to end the infighting because Jund al-Aqsa will have the protection of the powerful Fatah al-Sham Front.

But the Syrian Observatory for Human Rights reported intense fighting after the declaration between Jund al-aqsa and Ahrar al-Sham in the northern province of Idlib.