LISBON (Reuters) – Rough waters forced authorities on Wednesday to postpone a salvage operation for a ship packed with luxury cars that have been on fire for a week in the middle of the Atlantic Ocean, a port official said.

With teams unable to board the Felicity Ace, heavy tug boats sprayed water to cool the vessel, which is carrying around 4,000 vehicles including Porsches, Audis and Bentleys.

The 22 crew members were evacuated last Wednesday, the day the fire began.

Some of the vehicles are electric and their lithium-ion batteries have made the fire very difficult to extinguish, port officials have said.

João Mendes Cabeças, the captain of the nearest port on the Azorean island of Faial, said the blaze had lost its intensity, probably because there was little left to burn.

Salvage teams hoped to board the ship, which is is adrift around 170 km southwest of the Portuguese islands of Azores, to assess its condition and start preparing it for towing, the navy said in a statement on Tuesday.

It is unclear if the vessel will be towed to the Bahamas or Europe.

Cabeças told Reuters bad weather prevented the team from boarding the ship. Waves as high as 2.5 meters battered the coast of Faial on Wednesday, Portugal’s weather agency IPMA said.

The salvage team was expected to be flown to the ship on a helicopter belonging to the Portuguese air force, which will decide on Thursday if the operation can proceed, Cabeças said.

Ship manager Mitsui O.S.K. Lines Ltd (MOL) said in a statement on Tuesday the vessel was still on fire but stable, and that no oil leak had been reported so far. It did not respond to a Reuters request for comment on the cause of the fire.

Insurance experts said the incident could result in losses of $155 million.

(Reporting by Catarina Demony; Editing by Barbara Lewis)