Frigate goes down off Sri Lanka as Washington and Israel step up their offensive and promise to hit ‘deeper’ targets in Iran

A torpedo fired by a US submarine sank an Iranian warship off the south coast of Sri Lanka as the Trump administration followed through on its threats to destroy Tehran’s military and political leadership.

At least 87 Iranian sailors were killed in the attack on the Iris Dena. The frigate was sailing in international waters as it returned from a naval exercise organised by India in the Bay of Bengal. The torpedo strike prompted questions from former US officials about whether Washington’s aim of eliminating all of Iran’s military breached international law.

The incident came as the US-Israeli air ᴀssault on Iran continued for a fifth day, with Washington officials warning that strikes would soon hit targets “deeper” in Iran. US forces also targeted pro-Iranian militias in Iraq, while the Iranian Revolutionary Guard Corps (IRGC) announced that it would continue missile and drone strikes on targets throughout the Middle East.

Pete Hegseth, the ex-Fox News host now leading the Pentagon as defence secretary, confirmed that the US sank the Iris Dena 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,” Hegseth said. He said the attack was carried out late on Tuesday night.

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

It is in fact one of only a few instances of a submarine sinking a ship since the second world war, and a rare example of an attack on a foreign warship not taking part in open hostilities.

According to Sri Lanka’s foreign affairs minister, Vijitha Herath, coastguards received a distress call from the Iris Dena at 5.08am on Wednesday. Crew members described the incident as an explosion.

“By 6am we dispatched a naval vessel and by 7am the second naval vessel,” Herath said. He said Sri Lanka had an obligation to respond to the call for help because it was a signatory to the international convention on maritime search and rescue.

Sri Lankan officials said they had saved 32 people from the ship, which was believed to be carrying 180 crew. Emergency responders retrieved 87 bodies from the water. Navy spokesperson Buddhika Sampath said rescue boats arrived at the site of the attack to find that the Iranian frigate had already sunk, leaving just an oil slick.

The frigate was outside Sri Lanka’s territorial waters but still within its economic zone, 44 nautical miles (81km) off Galle.