BEIRUT (AP) — Syrian activists say clashes have broken out between rebels and al-Qaida-linked militants in the opposition's main stronghold in northwestern Syria.

The Britain-based Syrian Observatory for Human Rights says 11 people, among them 3 civilians, have been killed on both sides.

The infighting comes days after a powerful jihadist rebel faction adopted the Syrian revolutionary flag, in a symbolic break with an al-Qaida-linked faction, called the Levant Liberation Committee, which dominates the northwestern Idlib province.

Local media activist Ahmad Abazeid tweeted on Wednesday that rebels ambushed a number of checkpoints and a judicial building belonging to the al-Qaida-linked factions in Idlib.

The extremists' Abaa' News Agency said their opponents deployed tanks in the fighting and warned that they might deploy their own heavy weaponry.