New Zealand will hold a court of inquiry into the loss of the ship, which was one of nine in its navy. The cause of the disaster is not known.

An oil spill is “highly probable” from a grounded New Zealand navy ship which sank and caught fire off the coast of Samoa, the Pacific island nation’s acting prime minister said late Sunday.

Officials in Samoa are conducting an environmental impact assessment in the area where the ship sank on Sunday morning, acting Prime Minister Tuala Tevaga Iosefo Ponifasio said in a statement.