The Sri Lankan government imposed a curfew on a city north of Colombo, the capital, Sunday to contain religious tensions as officials prepared to reopen schools after the Easter bomb attacks that killed 257 people.

A senior police officer said the night curfew was imposed to prevent an escalation of mob violence after attacks occurred in Negombo, where over 100 Christians died in a church bombing two weeks ago.

“At least two motorcycles and two three-wheel taxis have been damaged in the clashes,” the police officer told AFP. “We declared a curfew till 7.00 am to contain the unrest.”

There were no immediate reports of casualties.

The country’s main international airport is located in the area, but police said airport traffic was not disrupted, adding that Elite Special Task Force commandos were patrolling the streets.

The senior officer said an investigation was underway into the clashes.

Tensions gripped Negombo as the authorities prepared to reopen public schools after an extended Easter vacation following the suicide attacks blamed on a local jihadist group linked to ISIS.

The country has been under a state of emergency since the suicide bombings. Security forces and police have been granted sweeping powers to arrest and detain suspects for long periods.

– with reporting by AFP