An unarmed Iranian drone has flown dangerously close to a US fighter jet over the Persian Gulf in what has been described as an "unsafe and unprofessional" encounter, by US authorities. The US Navy said the unmanned aircraft flew as close as 100ft (30m) from the US warplane.

Incidents like these have increased over the Persian Gulf ever since the US boosted its cooperation with the Sunni-oriented Saudi Arabia, the main regional rival of Shia-inclined Iran. Tensions, which had cooled down slightly after the landmark nuclear agreement between Iran and the US, have begun to rise after the Trump administration took charge of the White House.

The US military's Central Command said on Tuesday, 8 August that the Iranian drone did not respond to repeated radio contact. This has forced the F/A-18E Super Hornet jet to take evasive action while it was attempting to land on the USS Nimitz aircraft carrier.

"The dangerous manoeuvre by the QOM-1 [drone] in the known vicinity of fixed-wing flight operations and at coincident altitude with operating aircraft created a collision hazard and is not in keeping with international maritime customs and laws," said a statement from the US Defense Department.

The jet was in a holding pattern thousands of feet away from the warship when the drone approached the aircraft at about 1pm local time on Tuesday.

The department added this was the 13th time an "unsafe" interaction had taken place between Iranian and American forces since January 2017. Though there have been several such incidents in the past, this was the first time an Iranian drone has flown dangerously close to a US fighter.

The Super Hornet was thought to be part of the Strike Fighter Squadron (VFA) 147 and was at the international airspace when the incident occurred. The Iranian drone was identified as unmanned aircraft QOM-1.

Only in July, a US Navy warship fired warning shots at an approaching Iranian naval vessel, which ignored radio calls, in the Persian Gulf.

Iran drone buzzes US fighter jet
An F/A-18F Super Hornet jet flies over the USS Gerald R Ford as the US Navy aircraft carrier in this file photoHandout via Reuters