NEW DELHI (AFP) — India’s coast guard said it was battling to extinguish fires raging on a container ship carrying “hazardous” cargo off the southern coast to prevent a “potential ecological disaster.”

The 268-meter Singapore-flagged container vessel MV Wan Hai 503, carrying 22 crew members — four of whom are missing — caught fire about 78 nautical miles off India’s Beypore port on Monday.

Photographs released by the coast guard soon after the blaze broke out showed heavy containers scattered about the vessel, as if hurled up by a powerful explosion. Since then, fire has engulfed the ship.

“The vessel is carrying 2,128 metric tons of fuel and hundreds of containers, including hazardous cargo, posing a serious risk to the marine environment and regional shipping routes,” the coast guard said in a statement late Wednesday.

It did not provide more details on the contents of the cargo, but said that “the situation remains critical.”

Eighteen crew members were rescued by the Indian coast guard and navy. Four crew — one from Indonesia, two from Taiwan and one from Myanmar -- were listed as missing.

The coast guard said it had “winched five salvage team members” and a diver onto the burning ship.

“With the fire yet to be fully extinguished, efforts to establish a towline and pull the vessel away from the coast are underway to prevent a potential ecological disaster,” it said.

“Intensive firefighting efforts... have significantly reduced visible flames,” it added.

“However, the fire remains active in the inner decks and near fuel tanks.”

Seven vessels, including five coast guard vessels as well as airplanes and a helicopter, were engaged in trying to put out the fire.

The MV Wan Hai 503 container ship is the second to run into trouble off India’s southern coast within weeks.