A ferry has capsized in eastern Sri Lanka, killing at least six people, a navy spokesperson said.

Twelve people have been rescued and the search for others is continuing, Captain Indika de Silva said.

It was not immediately clear how many people were on the ferry or what caused it to overturn.

Four children were among the dead, according to a policeman and a hospital worker.

The ferry was travelling from Kurinchakeni to the town of Kinniya along the country's eastern coast, about 160 miles north east of the capital Colombo, the navy spokesperson said.

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

However, the bridge that connects the two towns has been closed for repairs, forcing people to use rudimentary vessels to cross the river, said Naazik Majeed, a social activist in Kinniya.

Angry residents burned tyres and surrounded government offices, blaming officials for the accident.