COLOMBO - MORE than 50 police and prison officials were injured on Sunday by inmates at Sri Lanka's main jail in the capital Colombo after authorities launched a drugs raid, officials and doctors said.

Convicts beat up police as they stormed the Welikada prison to search for hidden narcotics as part of a nationwide crackdown on illegal drugs, police said. Five prison officials and 46 policemen were brought for treatment at Colombo National Hospital, hospital director Hector Weerasinghe said.

'We were told that they were beaten up by prisoners when they tried to carry out a search,' Mr Weerasinghe said. 'Most of them have head and chest injuries.'

Police spokesman Prishantha Jayakody said there were no casualties among the convicts. 'Convicts in one of the Welikada prison wards launched the attack with sticks and stones,' Mr Jayakody said, adding that the police Criminal Investigations Department had been asked to probe the unrest.

Prisons deputy minister Vijithamuni Soysa said police had obtained a search warrant from a magistrate before entering the prison and similar search operations had been carried out in other prisons too, but without incident.

The clashes at the Colombo prison came as the police announced the results of an anti-narcotics drive that led to the arrest of over 11,500 suspects and the seizure of large quantities of heroin and cannabis. Overall, the raids, which started three weeks ago, have resulted in over 3,000 court cases, while many more will be filed soon, Mr Jayakody said.

Over 50 injured in prison clash