Iran's Foreign Minister Abbas Araghchi accused the US of committing an 'atrocity at sea' by sinking the Iranian frigate IRIS Dena in the Indian Ocean near Sri Lanka.
The warship, carrying nearly 130 sailors, was struck without warning by a US submarine in international waters, according to Tehran's first official acknowledgment of the incident.
Sri Lankan authorities say at least 84 sailors died while 32 survivors were rescued and taken to hospital in Galle.
The sinking marks a dramatic expansion of the conflict far beyond the Gulf, with rescue operations continuing for dozens still missing.
The incident has intensified hostilities across the Middle East, with Iran launching fresh attacks on Israeli and US bases while Israel says it has begun a 'large-scale' wave of strikes targeting Tehran.
