The report by Fox News quoted United States naval sources as confirming that the Iranian ship, whose crew was manning firing stations in readiness for battle, came within a kilometer of the American destroyer Mahan.
Iran views the USA presence in the area as a provocation and the Revolutionary Guard occasionally fires missiles or rockets near us ships.
Chernitzer said the Iranian vessel came within 1,100 yards (1,005 metres) of the destroyer, prompting the US Navy to issue warning messages, twice blast the internationally recognised five-whistle danger signal and deploy "a flare to determine the Iranian vessel's intentions". The Iranian vessel reportedly had its weapons manned.
NAVCENT assessed this interaction as unprofessional due to the Iranian vessel closing the distance to the U.S. ship in violation of the maritime "rules of the road", CENTCOM continued. The paramilitary Islamic Revolutionary Guard Corps Navy (IRGCN) finally turned away and sailed off after the warning shot was sacked, ABC News reports.
This unusually tense incident was not the first of its kind in the Persian Gulf.
Since the nuclear deal with world powers, the hardline Revolutionary Guard has stepped up its encounters with the US.
In 2016, there were 35 incidents of unsafe or unprofessional behavior by the Middle Eastern nation's ships, the site concludes. "With Monday's event, there have been seven so far in 2017".
This latest incident is among a growing list of Iranian provocations against USA forces, mostly maritime, in the region.