Hundreds of anti-regime protesters have once again poured onto the streets in Saudi Arabia's oil-rich Eastern Province to call for the release of thousands of political prisoners in the kingdom. The latest protests took place in the eastern city of Qatif on Wednesday night as demonstrators also called for political freedom and social equality. Activists say regime forces opened fire on protesters in a nearby area. No casualties have yet been reported. Saudi Arabia's east has been the scene of anti-government protests over the past months with demonstrators demanding rights reform, freedom of expression and the release of political prisoners. Saudi activists say there are more than 30,000 political prisoners, mostly prisoner of conscience, in jails across the Kingdom. Activists say most of the detained political activists are being held by the government without trial or charges and that they have been arrested for merely looking suspicious. Some of the detainees are reported to have been held without trial for more than 16 years. Attempting to incite the public against the government and allegiance to foreign entities are usually the ready-made charges against political dissidents. According to the Saudi-based Human Rights First Society (HRFS), the detainees were subject to both physical and mental torture. Last month Saudi security forces opened fire on anti-government protesters in Qatif, killing five of them.