Officials in New Delhi say that an Iranian warship that was sunk by a U.S. submarine near Sri Lanka had participated in naval exercises hosted by India before heading out into international waters in the Indian Ocean on its way home.

By Humeyra Pamuk WASHINGTON, March 6 (Reuters) - The United States is pressing Sri Lanka's government not to repatriate the survivors from the Iranian warship it sank this week, as well as the crew of a second Iranian ship that is in Sri Lankan custody,

At least 87 sailors were killed after the US attack on the 'IRIS Dena', an Iranian Moudge-class frigate, that was on its way home after participating in the Indian Navy's IFR 2026

It has also asked Sri Lanka to not send back the crew of another Iranian ship, IRIS Booshehr, that is in Sri Lankan custody.

The Indian government had quietly approved a different Iranian ship the IRIS Lavan to dock at the southwestern port of Kochi before the US Navy sank the Iranian warship IRIS Dena off the coast of Sri Lanka,

Iran sought permission for IRIS Lavan to dock at Kochi days before a US submarine torpedoed Iranian frigate IRIS Dena near Sri Lanka.

The reported sinking of the Iranian warship IRIS Dena by a US submarine using a Mark-48 torpedo in the Indian Ocean has triggered debate among military lawyers and analysts about whether the strike was lawful under international law.

These rules have developed over centuries as states sought to regulate the conduct of conflict at sea while still allowing navies to operate effectively.