COLOMBO: A ferry capsized in eastern Sri Lanka on Tuesday, killing at least six people, a navy spokesperson said.

Twelve people have been rescued and the search for others is continuing, navy spokesperson Capt. Indika de Silva said. It wasn’t immediately clear how many people were on board the ferry or what caused it to overturn.

Four children were among the dead, according to a policeman and a hospital worker who spoke on condition of anonymity because they weren’t authorized to talk to the media.

The ferry was traveling from Kurinchakeni to the town of Kinniya along the country’s eastern coast and about 260 kilometers (160 miles) northeast of the capital, Colombo, the navy spokesperson said.

Ferry accidents are relatively rare in Sri Lanka because many locations are now connected by bridges.