Iran attempted an unsuccessful test launch on Tuesday of a cruise missile from a submarine in the strategic Strait of Hormuz.
Two US officials told Fox News that an Iranian Yono-class “midget” submarine conducted the missile launch, but the test failed.
North Korea is the only other country that operates this kind of sub, according to the report.
The report did not detail the size or range of the missile or its warhead payload.
Last month, Iran’s navy deployed new anti-ship missiles, called Nasir, boasting that they could be fired from land or ship-based launchers. The cruise missile was test fired during the “Velayat 95” Iranian military drills in the Persian Gulf in February.
Iran claimed another ballistic missile test in March, a week after a US vessel in the Strait of Hormuz was forced to change course after being harassed by Iranian fast boats in the strategic waterway.
The Strait of Hormuz is a narrow waterway connecting the Persian Gulf to the Indian Sea through which a fifth of the world’s oil supply passes, making it a key strategic asset.
The Islamic Republic has previously harassed US Navy ships in the Persian Gulf and around the Strait of Hormuz, with the most notable case being Iran’s capture of 10 US Navy sailors in January 2016, who had drifted into Iranian waters after experiencing mechanical problems.
US President Donald Trump tweeted on February 2 that he had formally placed Iran “on notice” after it tested ballistic missiles capable of carrying nuclear warheads in January.
There was scant detail from the White House as to what the warning meant in practical terms. It remains to be seen if the White House will push for sanctions this time around.
The US Navy has a large presence in the Persian Gulf, where its Fifth Fleet is headquartered, and Iran has threatened on numerous occasions to attack US ships operating in the area.
Cruise missiles — such as the Nasir — are not covered by UN Resolution 2231, which was passed shortly after the nuclear deal with Iran was signed in July 2015 and calls on Tehran “not to undertake any activity related to ballistic missiles designed to be capable of delivering nuclear weapons, including launches using such ballistic missile technology.”
Iran argues that its ballistic missile program is also not covered by the resolution because it does not have a nuclear weapons program.