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

Twenty people have been rescued but it is not certain how many people were on the ferry, spokesman Nihal Talduwa said.

Four children were among the dead and another child is in intensive care, Mr Talduwa added.

Navy divers suspended rescue efforts after searching the area of the lagoon where the rudimentary vessel overturned, Mr Talduwa told the Associated Press, but will remain on standby.

It was not immediately known what caused the ferry to capsize.

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.