Earlier, three districts were brought under curfew in response to mob attacks on several Muslim-owned businesses and mosques. Army chief Mahesh Senanayake warned of maximum force against those violating the curfew.
Prime Minister Ranil Wickremsinghe in a message appealed for people to remain calm and not to be swayed by false information.
He said security forces are working tirelessly to ensure the security of the country but such civil unrest increase their burden and hamper ongoing investigations.
Parliament speaker Karu Jaysurya in a message said future of Sri Lanka will be decided by the way people behave in next few days.
He said if communal violence cannot be prevented, terrorists will be able to legitimize their crime, as they did in 1983.
Social media sites were blocked for the third time since Easter attacks for preventing rumors to spread.
Hate crimes has been on the rise against Muslims following Easter Sunday attacks which killed over 250 people including 45 foreigners.
An area in Negombo faced similar attacks last week while several social media posts are in circulation calling for boycott of Muslim businesses.