Police and politicians backed by the country's former strongman President Mahinda Rajapaksa joined anti-Muslim riots that rocked Sri Lanka's Kandy district this month, according to witnesses, officials and CCTV footage reviewed by Reuters.

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.

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.