US bombs Iranian warship invited by India for naval exercise

The country also disclosed that around 180 people were believed to have been aboard the Iris Dena, based on the ship's documentation.

The US announced on Wednesday that it sank an Iranian warship returning from a naval exercise organised by India in the Bay of Bengal, in the north of the Indian Ocean.

The warship was sunk by a torpedo fired by a US submarine off the south coast of Sri Lanka, leaving 87 Iranian sailors dead and about 100 others missing, according to Sri Lanka’s Foreign Ministry. The US made no effort to rescue the survivors.

Sri Lanka also disclosed that, based on the ship’s documentation, around 180 people were believed to have been aboard the Iris Dena.

The US attack on the warship, which was not taking part in the hostilities, expands the war beyond the Gulf countries to the Indian Ocean and to India’s backyard.

Reuters reports that the incident occurred near Sri Lanka’s Exclusive Economic Zone, in the international waters off the southern coast near Galle.

It is also considered one of the few cases of a submarine sinking a ship since the Second World War.

The IRIS Dena, a frigate belonging to the Iranian navy’s Southern Fleet, arrived in Visakhapatnam in mid-February for the International Fleet Review (IFR) and the multilateral exercise (MILAN-2026).

Around 74 nations participated in the exercise, excluding the US. Iran was invited to and participated in the exercise.

The US Navy’s guided-missile destroyer USS Pinckney was expected to participate, but withdrew shortly before the event.

“Indian Navy welcomes IRIS Dena, of the Iranian Navy, on her arrival at Visakhapatnam… reflecting long-standing cultural links between the two nations,” India’s Eastern Naval Command had said at the time.

The ship was returning to Iran when the US bombed it, in what many observers say was a violation of international law.

The Secretary of State, Pete Hegseth, confirmed that the US sank the warship as it sailed close to the Sri Lankan coast.

The Pentagon released black-and-white footage of a Mark 48 heavyweight torpedo striking the frigate, sending a geyser of seawater into the air.

“An American submarine sank an Iranian warship that thought it was safe in international waters,” he said.

“It was sunk by a torpedo, a quiet death – the first sinking of an enemy ship by a torpedo since World War II. Like in that war, back when we were still the war department, we were fighting to win,” he added.

However, Iran has vowed revenge over the attack on its unarmed warship.

According to Iranian Foreign Minister Abbas Araghchi, the US “perpetrated an atrocity at sea, 2,000 miles away from Iran’s shores.”

“Frigate Dena, a guest of India’s Navy carrying almost 130 sailors, was struck in international waters without warning,” he wrote in a post on X.

“Mark my words: The US will come to bitterly regret the precedent it has set, “ he declared.