An Indian sailor was killed on Wednesday when a merchant ship was attacked, reportedly by two torpedoes, off the coast of Oman.
It was the latest deadly incident affecting Middle East shipping, but neither Iran nor the US claimed responsibility for the strike.
The ship, the MV Cape Dao, was sailing under the flag of Antigua and Barbuda with 28 crew members on board.
The attack resulted in a fire in the engine room and the death of one crew member, said Oman's Maritime Security Centre.
An Omani warship came to the bulk carrier's rescue, with 27 people rescued and given medical treatment. The incident took place 4.6km off Musandam, an Omani exclave that borders the UAE.
The Indian embassy in Muscat said it was "deeply saddened" that one of its citizens had been killed in the attack. It said 19 of the crew were Indian.
A sailors' group, the Forward Seamen's Union of India, identified the person killed as Suraj Yadav from Uttar Pradesh. It said two torpedoes had struck the ship, hitting the engine room and sailors' accommodation.
In a letter addressed to Indian Prime Minister Narendra Modi, the union said its members were being "slaughtered in silence" in the Gulf of Oman and Strait of Hormuz as it appealed for an escort from Indian vessels. "We have lost many brothers," it said.
At least 23 sailors have been killed since the Iran war broke out in February, the International Maritime Organisation says. Some ships have been attacked by Iranian forces during a blockade of the Strait of Hormuz, a key route for the oil trade that runs between and Iran and the Gulf states.
The US military has also attacked ships during two separate blockades of Iranian ports ordered by President Donald Trump. Ships on the other side of the Arabian Peninsula have come under attack from Houthi rebels in Yemen.
