A notorious gang leader has died after he was shot inside a courthouse in Sri Lanka by a gunman disguised as a lawyer, say police.

Police say the gunman used a revolver which was smuggled in a hollowed-out book by a female suspect, who remains at large.

Gang leader Sanjeewa Kumara Samararathne had been escorted to court to face proceedings when he was shot. Police say he was a suspect in multiple murder cases.

The shooting in the capital Colombo is among a series of killings by rivalling gangs, which has persisted as authorities vow to crack down on gang violence in the country.

The gang leader, popularly known as Ganemulle Sanjeewa, had been in custody since he was arrested in September 2023.

Police said he had been escorted to the courthouse on Wednesday by a dozen police officers. He was taken to hospital after he was shot but was pronounced dead on arrival.

The gunman managed to flee the scene but was later captured by police. He has been identified differently by authorities and local media, but police say that he used several names.

Police have identified the female suspect as 25-year-old Pinpura Dewage Ishara Sewwandi.

Authorities have put out a notice promising a reward for anyone providing information on the woman. Police say they have also arrested a policeman and van driver suspected of helping the two suspects in the shooting.

Lawmakers discussed reining in gang violence in parliament on Wednesday, with an opposition MP calling it a "major security issue".

Health and mass media minister Nalinda Jayatissa, who in December had pledged to crack down on such criminal activity, said on Wednesday that the government would "take the actions of organised underworld gangs seriously."

The incident has also raised questions about security in the courthouse, with authorities currently reviewing security measures.

New security protocols are being implemented in the wake of the shooting, including deploying armed guards when certain people are brought to court. Armed security personnel are not typically allowed in court, justice minister Harshana Nanayakkara said on Thursday.

At least nine people have died this year in a spate of shootings blamed on gang rivalry, according to AFP citing police data.