A senior Iranian Army commander has vowed that Iran will exact vengeance for the 104 sailors martyred in the unprovoked US torpedo attack on the frigate Dena, describing the assault as a cowardly act of terrorism that international bodies have refused to condemn.

Deputy Army Commander for Coordination Rear Admiral Habibollah Sayyari made the pledge during a television program on Friday, emphasizing that the Dena was on a peaceful training mission when it was struck.

"Our ship had gone on a peace and friendship exercise and was training. It carried no combat weapons," Sayyari said.

"These martyrs were innocently killed. If they were men of the battlefield, why did they attack someone in such a treacherous manner? We will avenge these martyrs."

The Dena, a Moudge-class frigate, was torpedoed and sunk by the US Navy submarine USS Charlotte in international waters off the coast of Galle, Sri Lanka, on March 4.

The vessel was returning home after participating in the International Fleet Review 2026 naval exercise hosted by India — a multinational gathering to which Iran had been officially invited.

Sayyari criticized international and human rights organizations for remaining silent on what Iran calls a war crime.

"Why don't international and human rights organizations say anything about these issues? We have given 104 martyrs and the bodies of 20 of our martyrs remain in the sea and have not returned," he said.

According to the Iranian Army, a total of 136 personnel were on board the frigate when the USS Charlotte fired two Mark 48 torpedoes without warning. One hundred four were killed, 32 were wounded and rescued by Sri Lankan forces, and the remains of 20 crew members were never recovered.