RIYADH: Saudi authorities have freed 100 protesters arrested last week while staging a sit-in to demand the release of Islamist prisoners in the ultra-conservative city of Buraida, police said Wednesday.

"One hundred people were released" on Tuesday of the 176 people arrested in Buraida, capital of the northern Qassim province, said police spokesman Colonel Fahd al-Habdan.

"Procedures are continuing to free nine more prisoners," he said in a statement.

The official SPA news agency reported on Friday that Saudi police had arrested 176 people, including 15 women, for holding an illegal protest.

Authorities have accused the protesters of acting on behalf of "deviant groups" -- a term they usually use to refer to the Al-Qaeda jihadist network.

Saudi rights activists say those jailed are extremist political prisoners.

Demonstrations are banned in Saudi Arabia, an ultra-conservative Muslim kingdom that has remained relatively untouched by the Arab Spring uprisings.

Small groups of women have gathered almost daily in Buraida, north of Riyadh, to demand the release of imprisoned Islamist relatives, and dozens of protesters held a rare sit-in outside the Buraida prison in September.

A wave of deadly Al-Qaeda attacks in the kingdom between 2003 and 2006 prompted the authorities to launch a crackdown on the local branch of slain Saudi-born Osama bin Laden's group.