Tension has been high in Saudi Arabia's Eastern Province since last week after security forces detained Sheikh Nemr al-Nemr with almost daily protest rallies in the oil-rich region.
At least three people have been killed and many others injured in Riyadh's crackdown on demonstrations against the detention of al-Nemr.
There has been no word on al-Nemr's condition and whereabouts. The cleric was injured when regime forces attacked his car in Awamiyah to arrest him.
Since February 2011, Saudis have held demonstrations on an almost regular basis in the Kingdom's Eastern Province, mainly in Qatif and Awamiyah, calling for the release of all political prisoners, freedom of expression and assembly, and an end to economic and religious discrimination against the eastern region.
However, the demonstrations have turned into protests against the Al Saud regime, especially since November 2011, when Saudi security forces killed five protesters and injured many others in the province.