Salvage experts were attempting to tow a fire-stricken container ship that had been loaded with chemicals into the deep sea as the vessel started to sink off Sri Lanka’s main port, officials said.

Water submerged the MV X-Press Pearl’s quarterdeck a day after firefighters extinguished a blaze that had been burning for 12 days.

Experts were trying to tow the ship farther out to see because if it sank at its current position off the port of Colombo it would cause severe pollution, said navy spokesperson Indika de Silva.

The fire erupted on May 20 when the ship was anchored about 9.5 nautical miles north west of Colombo and waiting to enter the port.

The navy believes the blaze was caused by the chemicals being transported on the Singapore-flagged vessel.

It was carrying 1,486 containers, including 25 tons of nitric acid and other chemicals that were loaded at the port of Hazira, India, on May 15.

The blaze destroyed most of the ship’s cargo and polluted surrounding waters and a long stretch of the island nation’s famed beaches.

The Sri Lanka Ports Authority said salvage personnel had embarked on the vessel after dousing the fire and assessments were being carried out.

The vessel’s 25-member crew was evacuated last week after an explosion.

They include Philippine, Chinese, Indian and Russian nationals.