West Asia conflict | Why was Iranian vessel IRIS Dena, sunk by the US, in Indian Ocean?

Five days after the crisis in West Asia began following the coordinated strikes by the United States and Israel on Iran, the Indian subcontinent felt the ripples of the conflict on Wednesday, March 4. An Iranian warship was torpedoed by a United States submarine in the Indian Ocean off the coast of Sri Lanka during the early hours of Wednesday.

US Defence Secretary Pete Hegseth, confirming the strike, said at a Pentagon media briefing that it was the first sinking of an enemy warship by a torpedo since World War II. "An American submarine sank an Iranian warship that thought it was safe in international waters...Instead, it was sunk by a torpedo," Hegseth said.

The Associated Press, quoting Sri Lankan Navy, reported that 87 bodies were recovered and that 32 people were rescued following sinking of the warship.

So what was IRIS Dena, the Iranian vessel that was sunk by the US doing in the Indian Ocean?

IRIS Dena was part of Indian Navy's premier multilateral maritime exercise Milan. The mega exercise last month saw participation of 42 warships and submarines that included 18 ships from friendly foreign countries.

The warship had also featured in the International Fleet Review hosted by the Indian Navy in Vishakapatnam last month.

Former Indian Navy Chief Admiral Arun Prakash described the US action as a "senseless" and "inflammatory act".

"Sinking of Iranian warship, off southern tip of Sri Lanka, with heavy loss of life is a senseless & inflammatory act. Initiating another dimension of violence in this open-ended conflict, will spread alarm across the high seas & disrupt global seaborne commerce. Condemnable!," he said on social media.

The incident marks a major escalation of the conflict between the US and Iran outside of the Persian Gulf and throwing up questions relating to maritime security in the Indian Ocean that is largely considered as the backyard of the Indian Navy.

The Pentagon has also released a short video of the sinking of the Iranian frigate.

The warship IRIS Dena is a Moudge-class frigate and had nearly 180 crew members on board.

Sri Lankan officials said a major search and rescue operation was underway to rescue the survivors.