Photo taken on June 2, 2021 shows part of the X Press Pearl, a container ship burnt near the Colombo Port, in Colombo, Sri Lanka. The Sri Lankan Navy on Wednesday said that operations to tow the burnt X Press Pearl ship had been halted after the rear end of the vessel had hit the sea bed.(Photo: Xinhua)

A black box from a ship loaded with chemical and plastic that is sinking off Sri Lanka has been located, officials said Sunday, as investigators probe what caused the vessel to catch fire.

The Voyage Data Recorder (VDR), also known as a maritime "black box," enables investigators to review procedures and instructions ahead of an accident.

Sri Lankan authorities said that they hope it will provide details of the ship's movements and its communications with the harbor in the capital Colombo, where it had been due to dock.

"The navy facilitated technicians to remove the VDR from the bridge which is still above the waterline," navy spokesperson Indika de Silva told AFP.

The Singapore-registered MV X-Press Pearl has been slowly sinking into the Indian Ocean since Wednesday after a fire that raged for nearly two weeks within sight of the coast.

The ship, carrying 25 tons of nitric acid and a huge amount of plastic raw materials, was heading to Colombo from Gujarat, India.

Sri Lankan officials have said an acid leak since May 11 may have sparked the blaze. Ports in Qatar and India had refused to offload the leaking nitric acid, they added.

Police on the island nation launched a criminal investigation, interviewing the vessel's skipper and chief engineer - both Russians - and its chief officer, an Indian, and seizing their passports.

Authorities are bracing for a possible oil spill after the stern submerged. There has been no sign of any leaks so far, they added.

Tons of microplastic granules from the ship swamped an 80-kilometer stretch of beach declared off-limits for residents. Fishing in the area was also banned.

AFP