More than 180 Tamil political prisoners have been moved from Magazine prison in Welikada after clashes between prisoners and guards led to at least 31 people having sustained injuries.
The Tamil prisoners were moved to the main complex of the prison and were reportedly transferred to another jail for their own safety, after riots took over Magazine prison.
Previous prison riots, notably in 2000, 1997 and 1983, have resulted in Tamil political prisoners being murdered by Sinhala mobs.
Several buildings have been set alight by the prisoners as they flung stones at prison guards, who retaliated by opening fire. There were also unconfirmed reports that three prisoners had been killed by the gunfire.
The violence erupted after guards launched a crackdown on drug smuggling inside the prison, with inmates claiming that food brought by relatives to the prison were banned. Prisoners were seen on the roof holding a banner calling for the removal of the prison chief.