Two Indian seafarers were killed and another was missing after United States forces struck a commercial tanker off the coast of Oman, amid the conflict in West Asia, the Forward Seamen’s Union of India said on Wednesday.

This came hours after New Delhi summoned a top American diplomat to register its protest against the strike in the Gulf of Oman, ANI reported.

The seaman’s union identified the two dead as Aditya Sharma, a deck cadet, and Shivanand Chaurasiya, an engine fitter, The Hindu reported. Chief Engineer Patnala Suresh is missing.

Earlier, the Ministry of External Affairs had said that three Indian crew members were missing and 21 others had been rescued from the Palau-flagged tanker Settebello.

The ministry then summoned Jason Meeks, the US Chargé d’Affaires in New Delhi over the attack.

On Tuesday, the US Central Command said that it had disabled the vessel Settebello after it violated the American blockade restricting maritime traffic linked to Iran. The ship was reportedly attempting to transport oil from Iran.

“A US aircraft fired precision munitions into the ship’s engine room after the crew repeatedly failed to comply with directions from American forces,” the military agency said.

The strike came a day after another tanker, Marivex, carrying 24 Indian seafarers, was also targeted by the US forces for allegedly violating the blockade. All 24 Indian crew members on board the Marivex were rescued.

On Wednesday, the ministry of external affairs condemned the attack on Settebello and reiterated its call for “immediate de-escalation of tensions and the conclusion of ongoing negotiations for a diplomatic solution so that peace and stability can return to the region”.

It added: “The targeting of commercial shipping and civilian infrastructure in the region must end, and free and unimpeded navigation and commerce through the international waterways in the region in keeping with international law must be restored at the earliest.”

Edited by Neerad Pandharipande.