The US military fired a missile at the engine room of the Gambia-flagged cargo ship Lian Star after it allegedly ignored more than 20 warnings while attempting to enter an Iranian port.
Washington said it has now stopped six ships from breaching its blockade of Iranian ports, while more than 100 vessels have been rerouted.
The incident comes as the US and Iran continue negotiations on extending a fragile ceasefire, with the Strait of Hormuz remaining a key flashpoint for global trade and energy supplies.