Curfews have been in place in the districts in the country's north-west since Sunday when a group of men smashed up Muslim-owned shops and a mosque in a dispute with a local shopkeeper.
"Don't laugh more, 1 day u will cry", the shopkeeper wrote.
Several mosques and Muslim homes were damaged in the attack in the district, the Muslim Council of Sri Lanka said, but the precise extent of damage and the number of arrests was not immediately clear.
Muslims have been subjected to hate comments since the Easter Sunday bombings.
Nalaka Kaluwewa, director general of the government information department, said: 'Social media blocked again as a temporary measure to maintain peace in the country'.
Nine suicide bombers, including a woman, carried out a series of devastating blasts that tore through three churches and three luxury hotels, killing 258 people and injuring over 500 others on April 21.
The violence is a direct fallout from the Eastern Sunday's suicide bombings.
The attacks were blamed on a local group which had pledged an oath of allegiance to Abu Bakr al-Baghdadi, the leader of the Islamic State in Iraq and Syria (ISIS) group.
Addressing a service here, Malcolm Cardinal Ranjith the Archbishop of Colombo, said everyone responsible for neglecting the intelligence and prior warnings on the attacks including the political leadership must be brought to book.
The Church received "specific information of two possible attacks against churches" and it was made a decision to call off the May 5 mass, a spokesman for Cardinal Malcolm Ranjith said on May 2.
Police curfew has been imposed in the Chilaw area with immediate effect, Police said. It has been reported that a mosque and few shops owned by Muslims were attacked by a mob.
The Sunday curfews came as Catholic churches held their first Sunday mass amid tight security.
"We call upon the members of the Muslim communities to be more patient and guard your actions and avoid unnecessary postings or hosting on social media", the ACJU said.
On Twitter, Sri Lanka's leading mobile phone operator Dialog said it had also received instructions to block the apps Viber, IMO, Snapchat, Instagram and Youtube until further notice.
"Several shops have been attacked", a senior police officer told Agence France-Presse.
In the wake of the attacks, Sri Lankan authorities, last month, banned two local Islamist groups, including the National Thowheeth Jama'ath (NTJ), and the splinter group Jamathei Millathu Ibrahim (JMI), affiliated to the Islamic State. Security forces and police have been given sweeping powers to arrest and detain suspects for long periods.
He added that it was safe for tourists to return to the Indian Ocean island nation.
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