U.S. will ‘bitterly regret’ attacking IRIS Dena: Iranian Foreign Minister

The official reaction from Tehran comes a day after a U.S. submarine attacked Iranian warship IRIS Dena, which sank in the Indian Ocean off Sri Lanka’s southern coast. At least 83 people were killed in the torpedo attack on Wednesday (March 4, 2026), while the Sri Lankan Navy rescued 32 injured sailors, who are currently undergoing treatment at a public hospital in the island nation’s southern Galle district.

Taking to social media platform ‘X’ Thursday (March 5, 2026) morning, Mr. Aragchi wrote: “The U.S. has perpetrated an atrocity at sea, 2,000 miles away from Iran’s shores. Frigate Dena, a guest of India’s Navy carrying almost 130 sailors, was struck in international waters without warning. Mark my words: The U.S. will come to bitterly regret precedent it has set.”

Frigate Dena was returning to Iran after participating in the International Fleet Review 2026, a global maritime exercise held in Visakhapatnam last week.  

Neither Sri Lanka nor India has responded to U.S. Defence Secretary Pete Hegseth’s remarks to Washington D.C.-based media on Wednesday, confirming the strike that has effectively brought the war in West Asia to the Indian Ocean. “An American submarine sunk an Iranian warship that thought it was safe in international waters. Instead, it was sunk by a torpedo,” Mr. Hegseth had said, terming it a “quiet death” and the “first sinking of an enemy ship” by a torpedo since World War II. “Like in that war,” he said, “we are fighting to win”.