COLOMBO, May 14 (Xinhua) -- At least one person was killed when clashes erupted in northwest Sri Lanka and the Gampaha District on the outskirts of capital Colombo on Monday, police said Tuesday.

Police said security had been heightened across the island and a curfew was in place in the North Western province to prevent a further escalation of violence.

Police added at least 13 people had been arrested over the clashes so far and a hunt was on for more suspects.

The army and police have urged people to remain calm and have warned of stern action against anyone involved in the violence.

The clashes erupted in the Kurunegala District in the North Western province on Monday morning when mobs took to the streets and destroyed mosques, businesses and homes.

Fears of ethnic violence have been growing in Sri Lanka following the Easter Sunday terror attacks on April 21, which killed over 250 people and injured 500 others.

A local radical group, named the National Thawheed Jammath, has been blamed for the Easter attacks.

Prime Minister Ranil Wickremesinghe, in a special statement released Monday evening, urged people to remain calm and adhere to the laws.

He said security forces had been entrusted with maintaining law and order and he requested the public to abide by their instructions to ensure peace is maintained.

Wickremesinghe on Tuesday morning visited Kuliyapitiya in the Kurunegala District which was one of the towns affected by the violence, to meet with the affected people and to discuss measures to ensure their security.