A major Tunisian security presence has surrounded the country's main religious center and prevented hardline Muslims from holding their annual gathering.

Police scuffled with rock throwing young men and fired tear gas in Kairouan on Sunday, where the Ansar al-Shariah organization had announced it would gather thousands for its annual conference.

Police also arrested the spokesman for the movement, Seifeddine Rais, who said Thursday the state would bear responsibility for any blood spilled if the conference was banned.

About 11,000 police surrounded the city this weekend and conducted patrols to prevent the conference from taking place because "of the threat it represented to security and public order."

Tunisia has seen a rise in ultraconservative Muslim groups, known as salafis, which have attacked what they call signs of impiety.