Sri Lanka has rescued 32 “critically wounded” sailors aboard the Iranian frigate IRIS Dena, which sank today just outside the island’s territorial waters, Foreign Minister Vijitha Herath says in an update according to AFP.

No information was immediately available on the cause of the explosion that sank the vessel, but Herath told Parliament that the injured sailors were taken to a hospital in the island’s south.

“We are keeping up a search, but we don’t know yet what happened to the rest of the crew,” an official from Sri Lanka’s defence ministry told AFP, dimming prospects for finding any more survivors.

Both Sri Lanka’s navy and the air force said they were not releasing footage of the rescue because it involved the military of another state.