Colombo, May 13 (IANS): Sri Lanka on Monday temporarily blocked social media websites and messaging apps, including Facebook, Viber and WhatsApp and reimposed curfew in certain areas after a post sparked anti-Muslim riots in several towns of the country.

A group of people had stormed into Chilaw town on Sunday following a controversial Facebook post by a Muslim shopkeeper about "an attack plan". Reports said that several people threw stones at mosques and attacked Muslim-owned shops and a man was also beaten up in the violence.

Amid the unrest, the Army fired shots in the air to disperse the mobs but the unrest spread to other towns, the Daily Mirror reported.

An overnight curfew was imposed in Chilaw and Kuliyapitiya, Bingiriya, Hettipola and Dummalasuriya areas and the social media ban was imposed to prevent circulation of fake news and incitement to violence.

The police reimposed the curfew in Kuliyapitiya, Bingiriya, Dummalasuriya and Hettipola on Monday till 4 a.m. Tuesday and said that "tough action will be taken against anyone disrupting the peace".

The latest unrest began as Catholic churches resumed Sunday mass for the first time since the Easter bombings which killed over 250 people and injured hundreds.

According to the the All Ceylon Jamiyyathul Ulama (ACJU) -- the main body of Islamic clerics -- there has been increased suspicion of Muslims after the April 21 bombings blamed on local Islamic group National Thowheed Jamath, which is believed to have links with the Islamic State (IS) that claimed the carnage.

Sri Lankan authorities say most of the 150 people suspected to have been linked to the last month's attacks have died or been arrested, but other communities in the country still fear that the government has not caught all potential militants.