An Iranian Navy frigate during training last month (bottom) [EPA Yonhap News]

The U.S. military sank an Iranian warship using a submarine as part of the large-scale military operation 'Epic Fury' against Iran, Secretary of Defense Pete Hegses announced on the 4th (local time).

During a briefing at the Pentagon near Washington D.C. on the same day, Secretary Hegses stated, "Yesterday, a U.S. submarine sank an Iranian warship that was believed to be safe in international waters."

He added, "It was sunk by a torpedo attack, a silent death," noting, "This is the first instance of a torpedo sinking an enemy vessel since World War II," and concluded, "We are fighting for victory."

Chairman of the Joint Chiefs of Staff Dan Kain also reported, "For the first time since 1945, a U.S. Navy fast attack submarine sank an enemy warship to the seabed with a single 'Mark 48 torpedo'."

Chairman Kain emphasized that this attack "demonstrates the incredible global reach of the U.S. Navy," stating, "Only America can track, locate, and destroy enemy military assets deployed overseas."

The attack mentioned by Secretary Hegses and Chairman Kain occurred during the explosion and sinking of the Iranian Navy frigate 'Iris Dena' near Sri Lanka in the Indian Ocean.

Reuters reported that the incident was caused by an attack from a U.S. submarine, citing three anonymous U.S. officials.

Furthermore, according to AFP and Reuters, Sri Lankan Minister of Foreign Affairs, Bijita Herath, informed parliament that the country had deployed two naval vessels and one aircraft to rescue the Iranian vessel sinking near Sri Lankan territorial waters.

He explained that 32 of the 180 crew members on board the frigate were rescued and transported to the hospital with injuries.

However, Minister Herath did not mention the remaining 148 crew members, leading to the assumption that they are missing.

Another Reuters report stated that at least 78 people were injured and 101 were missing, and quoted a Sri Lankan deputy foreign minister telling local television, "At least 80 people have died so far."

Earlier, the Iris Dena had sunk approximately 40 kilometers south of Sri Lanka at dawn and sent out a distress signal.

Less than an hour after receiving the distress signal, when a naval rescue team approached the accident site, the Iranian frigate had already completely sunk.

Sri Lankan media outlet Daily Mirror reported that the Iranian frigate had recently participated in the fleet review of 'Milan 2026,' a multinational naval exercise held in Visakhapatnam, southern India.