A US submarine torpedoed and sank an Iranian frigate off the southern coast of Sri Lanka, killing at least 87 sailors, in a significant escalation of hostilities between Washington and Tehran. The attack on the IRIS Dena occurred in international waters as the vessel was returning from a multinational naval exercise hosted by India in the Bay of Bengal.
US Defence Secretary Pete Hegseth confirmed the strike, stating that a Mark 48 heavyweight torpedo fired from an American submarine sank the Iranian warship late on Tuesday night. He described it as “a quiet death – the first sinking of an enemy ship by a torpedo since World War II.” The Pentagon released black-and-white footage of the torpedo hitting the frigate.
Sri Lankan officials reported receiving a distress call from the IRIS Dena at 5.08am on Wednesday. Rescue efforts saved 32 crew members, but 87 bodies were recovered. The frigate, which was carrying around 180 personnel, sank within its economic zone, 44 nautical miles off Galle, leaving only an oil slick.
The incident occurred as the US-Israeli air campaign against Iran entered its fifth day, with Washington warning of strikes on “deeper” targets inside Iran. US forces also targeted pro-Iranian militias in Iraq, while Iran’s Revolutionary Guard Corps continued missile and drone strikes across the Middle East.
Former US Air Force targeting expert Wes Bryant criticised the attack, arguing that the IRIS Dena was not posing an imminent threat and that the strike may have violated international law. Sri Lanka’s foreign affairs minister confirmed the country responded to the distress call due to its obligations under the international convention on maritime search and rescue.
