The demonstration on Friday was called by human rights and political groups on the eve of the world day of support for torture victims. 

The marchers, among them dozens of women, gathered in front of the United Nations offices with banners calling for the trial of those responsible for torture. 

They also demanded the repeal of a decree promulgated by King Hamad last October blocking courts from considering cases involving incidents that occurred before a general amnesty was declared in February 2001. 

Rights violations

Several demonstrations were held in 2002 calling for the trial of a former police colonel, Adil Jasim Flifil, accused by the opposition of torture and rights violations during anti-government troubles between 1994 and 1999.

Bahrain's Sunni Muslim government which presides over a majority Shia population has cleaned up its act in recent years following bloody disturbances in the 1990s.

According to Amnesty International's latest report on Bahrain: "In the wake of the wide-ranging reforms of 2001, concrete safeguards for human rights continued to be implemented.

Nevertheless, several journalists were prosecuted in connection with articles published."

The 2004 report went on to say that "prisoners went on hunger-strike in Jaw Prison, reportedly against ill-treatment and lack of access to lawyers. One hunger striker died."