Police on Saturday fired on thousands of rioting prisoners demanding freedom, killing at least three and wounding more than 90, prison officials said. At least 33 prison guards were injured, 12 of them hospitalized, after prisoners stormed the prison's main gate with iron rods and sticks, said a police spokesman who could not be identified under briefing rules. About 5,000 convicts and detainees awaiting trial took part in the riot at Dhaka Central Jail, and some tried to scale the walls, a senior police official said on condition of anonymity. Police fired bullets and several tear gas shells. State television said three prisoners were killed. The state BSS news agency said the riot was continuing late Saturday, and some prison wardens were taken hostage. Hundreds of police surrounded the prison. Prisoners later waved blood-stained shirts from the roofs and threw two slips of paper with written messages for journalists standing outside the prison compound. In one message, the prisoners claimed that 20 to 50 prisoners were killed in police firing and between 100 and 300 were injured. The other message demanded that the prisoners be released because their crimes were small compared to those of Kader Siddiqui, an opposition political leader convicted of treason and sentenced in absentia for 12 years in prison. Siddiqui, who fled to neighboring India after the assasination of political ally President Sheik Mujibur Rahman in 1975, returned to a hero's welcome this month. The unrest started Friday when some prisoners who were jailed during the four years of martial law rule under former President Hussain Muhammad Ershad protested their detention and demanded they be released. Other prisoners joined in the protest. Ershad, a former army general, seized power in a 1982 coup and imposed martial law uptil 1986. He was arrested and placed under house arrest early this month following seven weeks of nationwide protests. Police have charged Ershad and several former ministers with corruption and abuse of power. Last week, the caretaker government that replaced Ershad freed 167 prisoners when it celebrated the nation's 19th year of independence from Pakistan.