A drone fired from Iran struck a Japanese-owned chemical tanker in the Arabian Sea on Saturday, the US Department of Defense said, an attack that came at a time of heightened fears of maritime trade being targeted further west in the Red Sea and Gulf of Aden.

The US military remains in communication with the merchant vessel Chem Pluto as it continues toward a destination in India, the Pentagon said in a statement.

The Indian Navy’s explosive ordnance disposal specialists will embark MV Chem Pluto when it reaches the Mumbai harbour on Monday to sanitise the vessel and undertake further investigation, the navy said in a statement on Sunday. It is being escorted by Indian Coast Guard Patrol vessel Vikram.

The Indian Navy and the coast guard deployed their assets to aid MV Chem Pluto, which was carrying chemicals from Saudi Arabia’s Jubail port to New Mangalore. It was struck roughly 217 nautical miles from Porbandar around 11.30 am on Saturday, according to the United Kingdom Maritime Trade Operations (UKMTO).

The incident comes at a time when the region is facing an array of security challenges including Houthi militia targeting commercial shipping in the Red Sea after the Israel-Hamas conflict began on October 7, and the apparent resurgence of piracy. The Iran-backed Houthi rebels declared their support for Hamas.

“The naval maritime patrol aircraft (P-8I) over flew MT Chem Pluto at 1315 h on 23 Dec 23 and established contact with the crew. The crew reported all 22 crew members to be safe and that the fire had been extinguished. The navy also communicated details of the developing situation to all Indian maritime agencies for rendering necessary assistance,” the navy statement said.

INS Mormugao established communication with merchant ship in distress on Saturday evening to ascertain if any assistance was required, it said. Vikram, a coast guard patrol vessel, was also present at the scene and was directed to escort MV Chem Pluto to Mumbai, it said.

“The vessel with 22 crew members (21 Indian and one Vietnamese) was reported on fire after being hit by a projectile at around 0745 h on 23 Dec 23 likely to be a missile or drone,” the statement added.

Last month, an Israeli-owned cargo ship was hit in a suspected drone attack by Iran’s Islamic Revolutionary Guard Corps in the Indian Ocean, the AFP quoted a US official as saying.

The hit on the vessel follows drone and missile attacks in the Red Sea by Iran-backed Houthis, who say they are supporting Palestinians under siege by Israel in the Gaza Strip, on commercial shipping, forcing mariners to change course and take longer routes around the southern tip of Africa.

On Saturday, an official in Iran’s Revolutionary Guard warned of the forced closure of other waterways unless Israel halted its war with Hamas, the AFP report said.

“With the continuation of these crimes, America and its allies should expect the emergence of new resistance forces and the closure of other waterways,” Mohammad Reza Naqdi said, quoted by Iran’s Tasnim news agency.

In a security notification issued on Saturday, UKMTO said it received a report of “an attack by Uncrewed Aerial System (UAS) on a vessel causing an explosion and fire.” It said the incident took place 200 nautical miles south-west of Gujarat’s Veraval coast.

The master in command of the vessel is an Indian: Deepesh Badikkihil.

After receiving information on Chem Pluto on Saturday, the Mumbai-based Maritime Rescue Coordination Centre (MRCC) activated the International SafetyNET to rush the nearest merchant vessel in the area to inspect the vessel. The SafetyNET is the service for broadcasting and automatic reception of maritime safety information via satellite communications.

MV Merlin, which was in the area, went to check on MV Chem Pluto. Merlin reported that the Pluto crew was safe, but the ship’s power generation had failed.