A fire and explosion aboard the Singapore-flagged containership Wan Hai 503 have left four crew members missing off the southwest coast of India.

The incident occurred on Monday around 12.30 hrs Singapore time, some 80 km southwest of Azhikkal, Kerala. The 4,333 teu vessel, operated by Wan Hai Lines, had 22 crew members onboard at the time.

Eighteen crew members were rescued from lifeboats by a passing vessel, though some sustained injuries. The Maritime and Port Authority of Singapore (MPA) reported that search and rescue operations are underway, supported by the Indian Coast Guard and Indian Navy.

Dramatic images and videos posted by the Indian Coast Guard on the social media platform X showed heavy black smoke billowing from the ship and several containers damaged or displaced. According to Indian officials cited by Reuters, at least 40 containers fell into the sea following a series of explosions and fires.

Authorities continue to investigate the cause of the incident and are working to locate the missing seafarers: a Taiwanese national, two Indonesians, and one from Myanmar.

The 2005-built vessel was en route to Nhava Sheva in Mumbai from the Sri Lankan port of Colombo, according to AIS data.