Sri Lankan police said petrol bombs were hurled at a mosque on Thursday as hundreds of troops patrolled a troubled central district where violence has left three people dead.
Muslim-owned businesses were set on fire and vandalised in several parts of Sri Lanka, police said, days after an island-wide state of emergency was imposed to curb riots in Kandy.
Police announced 85 people had been arrested for rioting in the hill district, including the leader of a radical Sinhalese Buddhist group known for agitating against Muslims.
"We have arrested 10 key suspects, including Amith Weerasinghe, who orchestrated and led these attacks," police spokesman Ruwan Gunasekera told reporters in Colombo, adding that another 75 were detained.
Armoured vehicles and heavily-armed troops guarded Kandy, the epicentre of the violence where internet services remain suspended and an evening curfew is in place.
The government ordered the internet blackout after police discovered mobs of Sinhalese rioters were using social media to coordinate attacks on Muslim establishments.
More than 200 homes, businesses and vehicles have been torched in three days of violence by mobs from the mainly Buddhist Sinhalese majority.
A 24-hour curfew was imposed on Wednesday afternoon after a hand grenade exploded in the hands of an attacker, killing him and wounding 11 others, officials said.
The day-time curfew was eased following a calm night but schools were shuttered as tensions remain high in the tourist hotspot.
In Kuruvita, 125 kilometres south of Kandy, police said petrol bombs were lobbed at a mosque. Little damage was inflicted and three suspects are being pursued.
In Weligama, 240 kilometres south of Kandy, a Muslim-owned business was attacked, police said, while Muslim establishments were pelted with stones in at least two other locations outside Kandy.
Sri Lanka's telecoms regulator asked internet providers to block access to Facebook and other social media platforms to prevent the spread of anti-Muslim hate speech.
Police have already identified anti-Muslim messages being shared on social networks, including a video posted by a hardline Buddhist monk urging violence against Muslims.
Muslims in Kandy complained that security forces and police -- equipped with special powers to detain under the emergency provision -- were slow to react as the violence unfolded.
"The main junction is going up in flames. At the same time, the authorities are folding their arms and watching," said Muslim businessman M. Jaffer, as quoted in Thursday's DailyFT newspaper.
Appeals for peace  
Former Sri Lankan cricket captain Kumar Sangakkara alluded to the island's history of ethnic violence in urging his countrymen "to say no to racism".
"We have to make sure that in Sri Lanka anyone and everyone feels safe, loved and accepted regardless of ethnicity or religion," he said in a video posted to Twitter.
President Maithripala Sirisena toured Kandy on Wednesday and ordered security forces to use the full force of the law against troublemakers.
Military officials said more reinforcements were sent to the area on Wednesday night to assist police who resorted to teargas to disperse rioters the previous evening.
The United Nations has condemned the violence and urged Colombo "to ensure that appropriate measures are swiftly taken to restore normalcy in affected areas".
The Kandy region, 115 kilometres east of the capital Colombo, is popular with tourists as well as Buddhist pilgrims. 
"Shops are opening, and more people can be seen on the roads since the curfew was lifted," a police official in the area said by telephone.
Holidaymakers have been urged to avoid the hill resort, which is home to Sri Lanka's holiest Buddhist shrine, the Temple of the Tooth Relic.
The chief custodian of the Unesco-listed temple, Pradeep Nilanga Dela, said foreign tourists and pilgrims were flocking to the shrine despite the tensions.
The unrest began on Monday after a Sinhalese man died following injuries sustained at the hands of a Muslim mob last week. Conflict escalated when a Muslim man was found dead in a burnt building on Tuesday.
Parliament on Tuesday issued an apology to the island's Muslim minority for the latest violence targeting them in the Indian Ocean island.
Mobs also set fire to Muslim-owned businesses and attacked a mosque in the east of the country last week. Last November riots in the south of the island left one man dead and homes and vehicles damaged.
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