WELLINGTON – Two people were confirmed dead and another two were missing after an inter-island ferry sank in the Pacific archipelago of Vanuatu on Friday, with survivors forced to endure more than six hours adrift, officials said.

The ferry carrying 30 passengers and 13 crew sank in the early hours of the morning as it was sailing from Malekula to the capital Port Vila, Vanuatu Red Cross chief executive Jacqueline De Gaillande said.

“The accident happened at 2am this morning and we were aware of it at 8am,” she told AFP. “By 10am the boat had completely sunk in 800 feet (240 metres) of water.”

“Right now, we have 28 passengers safe and 11 crew. The bodies of two women passengers have been recovered and there is one crew member and one child missing.”

De Gaillande said the cause of the accident was unknown but the ferry had capsized before sinking.

“We had divers looking under there for the missing but when it started to go down they had to give up,” she said.

She said the survivors were “very weak” after spending so long in the water and many were being treated for unspecified injuries in Port Vila.

Ferries are a common form of transport in Pacific archipelagos such as Vanuatu, a chain of about 80 mountainous islands.