At least a dozen Syrian secret police have defected from an intelligence compound in a restive province near Turkey, the first major defection reported within the security apparatus leading the crackdown on protesters, activists said on Sunday.

A gunfight broke out overnight after the defectors fled the Airforce Intelligence complex in the centre of Idlib city, 280 kms (175 miles) northwest of Damascus, and ten people on both sides were killed or wounded, they said.

One activist in the city, who gave his name as Alaa, said army defectors based in the nearby Jabal al-Zawiya region were seen near the compound and helped the deserters escape in what appeared to be a coordinated operation.

Armoured vehicles from an army barracks outside Idlib were called in to help defend the compound. The sound of AK-47s and machineguns echoed till dawn, he said.

Opposition sources estimate the number of defectors from the security forces at several thousand, mainly army recruits from Syria's Sunni Muslim majority. President Bashar al-Assad's Alawite minority sect has a tight grip on the country's military and security apparatus.

(Reporting by Khaled Yacoub Oweis, Amman newsroom; editing by Tim Pearce)