A US submarine sank the IRIS Dena warship in the Indian Ocean about 19 nautical miles off Sri Lanka’s southern port city of Galle on Wednesday, killing dozens of sailors and dramatically widening ​Washington’s pursuit of the Iranian navy.

On Thursday, Sri Lanka began offloading 208 crew members from a second Iranian ship, the ​naval auxiliary vessel IRIS Booshehr, which had found itself stranded in Sri Lanka’s exclusive economic zone ⁠but outside its maritime boundary.

President Anura Kumara Dissanayake said his island nation had a “humanitarian responsibility” to take in the crew.

The torpedoing ​of the Dena, which US Defence Secretary Pete Hegseth described as “quiet death” —was the first such action by the United States since ​World War Two and a clear sign of the Iran conflict’s widening geographic scope.

The internal State Department cable, which was dated March 6 and has not been previously reported, said Jayne Howell, the charge d’affaires at the US embassy in Colombo, had emphasised to Sri Lanka’s government that neither ​the Booshehr crew nor the 32 Dena survivors should be repatriated to Iran.

It said, “Sri Lankan authorities should minimise Iranian attempts to ​use the detainees for propaganda.”

Sri Lanka Navy personnel assist Iranian sailors during a rescue operation after responding to a distress call from their vessel, the Iranian military ship, IRIS Dena, within Sri Lanka’s maritime search and rescue region, in the Indian Ocean, March 4, via Sri Lanka Navy

The State Department did not immediately respond to a request for comment.

Representatives for Dissanayake’s office and Sri Lanka’s foreign ministry ‌were not ⁠immediately available for comment.

The cable said Howell also told the Israeli ambassador to India and Sri Lanka that there was no plan to repatriate the crew to Iran.

The envoy asked Howell whether there was any engagement with the crew to encourage “defection”, the cable said.

A representative for the Israeli embassy in New Delhi did not immediately respond to a request for comment.

On Wednesday, Sri Lanka’s deputy ​minister for health and mass ​media, Hansaka Wijemuni, told Reuters ⁠that Tehran had asked Colombo for help repatriating the bodies of those killed aboard the Dena, but a timeframe to do so has not yet been determined.

The Dena had taken part in naval ​exercises organised by India in the Bay of Bengal last month and was returning to ​Iran when it ⁠was struck by a US torpedo.

A US official, speaking on condition of anonymity, told Reuters the Dena was armed when it was hit and the United States did not provide a warning before carrying out the strike.

The State Department cable said the second vessel, the Booshehr, ⁠will ​remain in Sri Lankan custody for the duration of the conflict.

Sri Lankan authorities ​said on Friday that they were escorting the Booshehr to a harbour on the eastern coast and moving most of its crew to a navy camp near Colombo.