Scores of Muslim mosques, homes and businesses were destroyed as mobs ran amok for three days in Kandy, the central highlands district previously known for its diversity and tolerance. The government declared a state of emergency and blocked social media platforms for a week to control the unrest.

The role of police and some local Buddhist politicians suggests the Sri Lankan government lost control of elements of its security forces, and that the violence was more than a spontaneous outbreak fuelled by fringe Buddhist extremists and hate-speech spread on social media.

Rajapaksa has denied that he or other leaders of his party were involved. Police said the allegations against officers and politicians were being investigated.

Victims and witnesses, whose accounts were partly backed by CCTV footage seen by Reuters, described members of an elite paramilitary police unit, the Special Task Force (STF), assaulting Muslim cleric and leaders. Local STF commanders declined to comment.

"They came to attack," said A.H Ramees, a cleric at a mosque where worshippers say they were beaten by police who were supposed to be protecting them. "They were shouting. There was filthy language. They said all the problems were because of us, that we were like terrorists."

Ruwan Gunasekera, a spokesman for the national police force, including the STF, said a special investigation unit was "probing the deficiencies of the police in the incident". A second unit was examining the role of political actors, he said.

The riots were the latest example of rising Buddhist nationalism and anti-Muslim sentiment in the region and have unnerved Sri Lanka's multi-ethnic coalition government, which ousted Rajapaksa in an election in 2015, according to analysts and two sources familiar with the government's deliberations.

Australian Associated Press