Muslims make up around 10 percent of Buddhist-majority Sri Lanka's 21 million population and Christians about 7.6 percent. Mob violence in central Sri Lanka targeting Muslim communities in March of a year ago prompted the government to declare a state of emergency.
Reports said that several people threw stones at mosques and attacked Muslim-owned shops.
Homes and mosques were also vandalised by large groups of people armed with sticks and blunt weapons, police said.
Police implemented a nationwide curfew from 9 p.m.to 4 a.m. for both Monday and Tuesday night, though police spokesman Ruwan Gunasekera said no one has reported any new assaults as of Tuesday.
Sri Lanka has had a history of ethnic and religious violence and was torn for decades by a civil war between separatists from the mostly Hindu Tamil minority and the Sinhala Buddhist-dominated government.
Soldiers began patrolling areas hit by the mob violence after police arrested 23 people from across Sri Lanka who allegedly perpetrated the assaults.
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.
According to the the All Ceylon Jamiyyathul Ulama (ACJU) - the main body of Islamic clerics - there has been increased suspicion of Muslims after the attacks blamed on local Islamic group National Thowheed Jamath, which is believed to have links with the Islamic State (IS) that claimed the carnage. "They were from out of town", an owner of an electronic goods store told AFP by telephone. "Perpetrators could face up to a 10-year jail term", Gunasekera told Reuters.
Abdul Bari, 48, told Reuters his small brick shop had been burned down with a petrol bomb.
A police source said seven of those arrested for the violence in Kottampitiya were young Sinhalese men from nearby Buddhist villages. Sri Lanka's police say they have either killed or arrested all those responsible for the bombings.
In over a dozen interviews in the hard-hit Kurunegala district northeast of Colombo, Muslims said attacks took place despite the presence of security forces.
Police Chief Chandana Wickramaratne reportedly warned that authorities would respond to riots with maximum force.
"It is no heroism in attacking Muslims and damaging their property - true heroism is to control and overcome oneself", Ranjith said.
One person was killed in Sri Lanka on Monday in the worst sectarian violence since the Easter Sunday bombings that killed more than 250 people. "The security forces have been given full powers to deal with those who violate the state of emergency and the islandwide curfew", he said.