Twenty-five people were killed ​and about 100 injured in clashes between ‌two groups of prisoners at a prison in Sri Lanka on Monday, two police sources ​and one hospital source told Reuters.

The ​clashes began on Sunday between convicted prisoners ⁠and those under detention at the ​prison in the coastal town of Negombo, ​about 35km north of the commercial capital city of Colombo, the sources said.

The trigger for ​the clashes was not immediately known.

Police ​sources said that areas within the prison were still ‌being ⁠cleared, with officials working to account for the dead and the injured.

“The military has been requested to provide support to the police, ​but at ​the moment ⁠they are on standby,” Army spokesman Brigadier Waruna Gamage told ​Reuters.

Visuals from Derana TV showed heavy ​police ⁠deployment outside the gate of the prison as a police bus carrying the injured ⁠inmates, ​some of them sprawled ​on its floor, left the premises.