Inmates clashed with administrative staff of the Magazine prison prompting guards to open fire, a police official at the scene said.
"So far 19 inmates have been brought out with injuries and taken to hospital," the police official said. "There could be more injured."
The inmates, who were protesting over poor quality of food and overcrowding, also set fire to some buildings.
In 2010, more than 50 police and prison guards were wounded in a clash with inmates of the same facility when the authorities tried to seize cell phones illegally used by prisoners.
Colombo: Prison guards opened fire on rioting inmates at Sri Lanka's main remand prison in the capital Colombo on Tuesday, wounding nearly 20 inmates, officials said.
First Published: Tuesday, January 24, 2012, 16:21