FIVE years after the end of a bloody civil war that pitted Sri Lanka’s ethnic-Sinhala-dominated government against members of its Tamil minority, fears are growing about mounting violence along another of the country’s fault-lines—religion. On June 15th Sinhala Buddhist mobs rampaged through three towns on the southern coast, burning and attacking Muslim businesses and homes. Families cowered in marshes and took refuge in mosques as crowds banged on doors, baying for Muslims to come out. Some carried clubs, others flung petrol bombs.

The violence sputtered for nearly two days. Four people, three of them Muslims, were killed, and about 80 were injured. Calm was restored only when the army stepped in on June 17th. Outnumbered, the police and their special forces had struggled to beat back the mobs. Angry Muslims say many stood by and did nothing.

The mobs were incited by an inflammatory speech from a Buddhist monk named Galagoda Aththe Gnanasara. A rabble-rouser like the Burmese monk, Wirathu, whom he recently visited, Mr Gnanasara leads an organisation called Bodu Bala Sena (BBS), or Buddhist Power Force, that supports militancy against minorities to preserve the dominance of the Buddhist majority. Muslims have been particular targets. Although just 10% of the population, they are making headway in business and finance. Most shops attacked this week were run by Muslims. Some were razed to the ground.

The BBS organised a rally in the town of Aluthgama at which Mr Gnanasara raged that any “marakkalaya” (a derogatory term for Muslims) who laid a finger on a Sinhalese was doomed. His timing was pointed. Three days earlier hundreds of angry people had surrounded the Aluthgama police station after a Muslim man assaulted the driver of a Buddhist monk following a traffic dispute. The monk claimed that he too had been wounded. The government was blamed for allowing the BBS meeting to take place so soon after the incident. The inspector-general of police said he had thought the rally would end peacefully. Muslim parliamentarians countered that they had tried hard to stop it from going ahead. Mr Gnanasara’s hate speech clearly violates the law. Nor is this the first time he has incited violence against Muslims. He has not yet been arrested for his latest speech, though on June 17th the police got a court order to stop another BBS rally. They have been authorised to shoot violators.

The local press has largely ignored or played down the rioting. As it was under way President Mahinda Rajapaksa was in Bolivia at the G77 summit, tweeting breezily about climate change. After being criticised for his apparent insouciance, he did take to Twitter again to pledge to “bring to book” those responsible. He has promised an investigation and has said the government will rebuild destroyed houses and shops. But his government will find it hard to portray itself as a staunch defender of its Muslim minority.