Anti-Muslim rioting has flared up again in central Sri Lanka despite a state of emergency, with Buddhist mobs burning mosques and Muslim-owned shops in at least two towns, residents said.

The police ordered a curfew across much of the region for a third day on Wednesday in a bid to calm the situation.

Sri Lanka Violence
Security forces stand near a vandalised building in Digana, a suburb of Kandy. after mobs swept through the town, burning at least 11 Muslim-owned shops and homes (Pradeep Pathiran/AP)

One resident, who requested anonymity out of fear of reprisal attacks, said two mosques and some Muslim-owned shops were attacked in two towns in the central hills. The extent of the damage could not be verified.

Anti-Muslim riots began on Monday after a Buddhist Sinhalese man died after reportedly being attacked by a group of Muslim youths.

Sri Lanka Violence
Police officers stand guard in Ambatenna, in central Sri Lanka (Rukmal Gamage/AP)

Sri Lanka has long been divided between the majority Sinhalese, who are overwhelmingly Buddhist, and minority Tamils who are Hindu, Muslim and Christian.

Meanwhile, an internet company official said the government has ordered popular social media networks to be blocked across a swathe of central Sri Lanka in an attempt to stop the spread of religious violence.

The official said the networks, including Facebook, Instagram, Viber and WhatsApp, were blocked in the central hills, scene of the violence. However, many people outside that region were also unable to access the social media sites.