Tehran, Mar 5: Iran’s Foreign Minister Seyed Abbas Araghchi on Thursday levelled a grave allegation against the United States of America, claiming that Frigate Dena, ‘a guest of India’s Navy carrying almost 130 sailors, was struck in international waters without warning’.

“The U.S. has 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. Mark my words: The U.S. will come to bitterly regret precedent it has set,” Araghchi wrote in a post on X.

A US submarine strike targeted the Iranian vessel off Sri Lanka’s southern coast, far from the Gulf and thousands of miles from Iran’s shores.

War in West Asia: Submarine torpedo strike

For the first time since World War II, a US Navy submarine has fired a torpedo in combat to sink an enemy vessel, a development that was first confirmed by Sri Lanka.

The Iranian frigate Iris Dena was struck on Wednesday in the Indian Ocean near Sri Lanka, with the Pentagon later releasing footage showing a single torpedo exploding beneath the ship’s stern and tearing through its hull.

The United States Defence Secretary Pete Hegseth described the sinking as a “quiet death,” while Gen. Dan Caine, chairman of the Joint Chiefs of Staff, said the torpedo achieved “immediate effect.”

Sri Lankan authorities said 32 Iranian sailors were rescued from the vessel, which is believed to have carried a crew of about 180.

The US military said the submarine launched a Mark-48 heavyweight torpedo — the Navy’s principal sub-launched anti-ship weapon since the 1970s. Designed to detonate beneath a vessel, the weapon creates a massive gas bubble that fractures the keel, often breaking a ship apart and sending it down rapidly.

First since World War II

According to The New York Times, the last time an American submarine fired a torpedo at an enemy ship was on August 14, 1945, when the USS Torsk sank a Japanese patrol escort near Maizuru, just days before the end of World War II.

While US submarines have since carried torpedoes during Cold War patrols and modern deployments, they have primarily been used for intelligence-gathering missions and launching cruise missiles in conflicts ranging from the 1991 Gulf War to operations in Afghanistan, Iraq, Libya and Yemen.

The sinking of the Iris Dena thus marks a rare return to a form of naval combat not seen in more than eight decades.