A US Navy attack submarine has sunk an Iranian warship with a single heavyweight torpedo in the stormy waters of the Arabian Sea, US defence sources say, marking the most dramatic naval clash yet in the spiralling confrontation with Tehran.

According to initial reports, the Virginia‑class submarine had been shadowing the Iranian vessel for hours as it maneuvered near busy shipping lanes used by oil tankers. When the frigate allegedly locked its fire‑control radar and closed distance, US commanders authorised a pre‑emptive shot. Seconds later, a Mark‑48 torpedo smashed into the ship’s midsection, tearing a gaping hole below the waterline and knocking out power almost instantly.

Nearby commercial crews describe a “thunderclap under the sea” followed by a rising column of smoke and frantic distress calls. Coalition helicopters and patrol craft rushed to the scene, plucking dozens of soaked, injured sailors from the dark water. Western intelligence estimates more than 140 crew were on board; many are still missing as search‑and‑rescue operations race against fading light and roughening seas.

Tehran has condemned the strike as “an act of state piracy” and vowed “severe revenge,” insisting the ship was on a routine patrol in international waters. Pentagon officials counter that the vessel was feeding targeting data for missile and drone attacks on US forces and commercial shipping, calling the engagement “clear self‑defence under international law.”

The sinking sends a chilling signal across world capitals: the shadow war beneath the waves is now fully in the open — and one miscalculation away from a wider naval conflict no one may be able to stop.