Sri Lankan officials say guards have opened fire on prisoners during a riot that left least 28 people wounded.

Tuesday's clashes took place at the Magazine prison in the capital, Colombo. Four guards were among those hurt in the unrest.

Authorities say rioting inmates set fire to a building to protest poor conditions at the jail.

Prison guards used tear gas and live ammunition to restore control after several hours of clashes.

In 2010, more than 50 police and prison officials were injured at Sri Lanka's Welikada jail when inmates resisted a search for narcotics and other prohibited items.