A man, presumably Muslim, was beaten up.
'Police and security forces have contained the situation, but these (unidentified) groups are still trying to create trouble'.
Sri Lanka has been on the edge since the April 21 horror when suicide bombers exploded themselves in three churches and three luxury hotels besides two other places. 'Security forces are assisting police who have been ordered to use maximum force to contain the violence'.
Sri Lankan authorities say most of the 150 people suspected to have been linked to last month's attacks have died or been arrested but many still fear that the government has not caught all potential militants.
"If not adequately dealt with, the recent violence has the potential to escalate even further", the advisers said in a statement.
Police said there were sporadic incidents of mobs throwing stones and torching shops, motorcycles and cars owned by Muslims.
Elsewhere in the province, mobs torched dozens of Muslim-owned shops, vandalised homes and mosques in a day of rioting.
"Several shops have been attacked", a senior police officer told Agence France-Presse.
The government also reimposed a ban on social media following the violent clashes.
Platforms were similarly blocked after the Easter attacks. He also appealed for calm urged the public not to be swayed by false information. Wickremesinghe said the violence by a handful of people only hampered the ongoing investigations into suicide bomb attacks by local Islamic extremist group National Thowheeth Jama'ath (NTJ).
Muslims huddled in the mosque for safety and requested that police fire their guns in the air to disperse the mob, but police refused, saying that the mob wanted to inspect the mosque for weapons.
Police arrested a group of men for the attacks but people in the mostly Buddhist district then demanded their release, military spokesman Sumith Atapattu said.
A man walks through a damaged shop after a mob attack in Minuwangoda on May 14, 2019, north of the Sri Lankan capital Colombo.
Internet service providers said they have been instructed by the telecoms regulator to block access to Facebook, WhatsApp, YouTube and Instagram in a bid to prevent the spread of messages inciting violence. Amid the heightened security, students are only allowed into schools after checks for explosives.