The violence erupted inside the prison, although authorities did not immediately disclose what triggered the confrontation or identify the victims.

The injured were taken for medical treatment, a hospital source told Reuters, while security authorities responded to the unrest at the prison.

Police officials did not immediately provide further details on the circumstances surrounding the incident or whether the situation had been fully brought under control.

The prison violence ranks among the deadliest incidents in a Sri Lankan correctional facility in recent years. Authorities had yet to announce whether an investigation had been launched into the clashes.

Further official information on the identities of those killed and injured, as well as the cause of the violence, was not immediately available.