US navy fires warning flare at Iran vessel in Arabian Gulf

The incident happened on Monday as the vessel attempted to draw closer to the USS Mahan despite the destroyer trying to turn away from it.

The US guided-missile destroyer USS Mahan sailing through the Suez Canal in 2009. AFP Photo / File

A US warship fired a warning flare at an approaching Iranian Revolutionary Guard vessel in the Arabian Gulf, a US official said on Wednesday, in the latest tense naval encounter between the two countries.

The USS Mahan, a guided-missile destroyer, had an "unprofessional interaction" with an Iranian Revolutionary Guard Corps Navy vessel on Monday in the international waters of the Gulf, said Lieutenant Rick Chernitzer, a spokesman for the Fifth Fleet, based in Bahrain.

The incident took place on Monday and the Iranian vessel came within 1 kilometre of the Mahan despite efforts by the warship's crew to turn away from it, said Lt McConnaughey.

"Mahan made several attempts to contact the Iranian vessel by bridge-to-bridge radio, issuing warning messages and twice sounding the internationally recognised danger signal of five short blasts with the ship's whistle, as well as deploying a flare to determine the Iranian vessel's intentions," Lt McConnaughey said.

"Eventually, the Iranian vessel opened the distance, steering a course away from Mahan," he said.

The US and Iran have had several encounters in the Arabian Gulf and the nearby Strait of Hormuz, through which a third of all oil traded by sea passes.

Iran regards the American presence as a provocation and its paramilitary Revolutionary Guard shadows US navy ships in the Gulf, occasionally firing missiles or rockets near by.

Since the nuclear deal with world powers, the hardline Guard has increased its encounters.

In January, the Mahan fired warning shots at the Revolutionary Guards in the Straight of Hormuz, a key gateway for global oil supplies.

The Pentagon identified 35 similar incidents in the first half of 2016 along, up from a recorded 23 incidents in 2015. There have been seven so far this year, Lt McConnaughey said.

Of the incidents last year, the worst involved Iranian forces capturing 10 US sailors and holding them overnight.

* Associated Press and Agence France-Presse