The increased use of drones by Iran and its allies for surveillance and attacks across the Middle East is raising alarms in Washington.
The United States believes that Iran-linked militia in Iraq have recently increased their surveillance of American troops and bases in the country by using off-the-shelf, commercially available drones, U.S. officials say.
The disclosure comes at a time of heightened tensions with Iran and underscores the many ways in which Tehran and the forces it backs are increasingly relying on unmanned aerial vehicles (UAVs) in places like Yemen, Syria, the Strait of Hormuz and Iraq.
Beyondsurveillance, Iranian drones can drop munitions and even carry out "akamikaze flight where they load it up with explosives and fly it intosomething", according to a U.S. official who spoke on condition ofanonymity.
Yemen'sIranian-backed Houthis have significantly increased their UAV attacks in recentmonths, bombing airports and oil facilities in Saudi Arabia, a main rival ofIran.
Last month, Irancame close to war with the United States after the Islamic Republic'sunprecedented shoot-down of a U.S. drone with a surface-to-air missile, a movethat nearly triggered retaliatory strikes by U.S. President Donald Trump.
Trump withdrew froma major 2015 nuclear deal last year and reimposed sanctions to cut off Iran'soil exports and pressure the Islamic Republic to negotiate over its ballisticmissile programme and regional policy.
The increased useof drones by Iran or its regional allies is a strategy aimed at pushing backand defending against pressure from the United States and foes like SaudiArabia and Israel, current and former security officials and analysts say.
Iran now flies twoor three drones over Gulf waters every day, the first U.S. official estimated,making it a core part of Tehran's effort to monitor the Strait of Hormuz,through which one fifth of the world's oil consumption flows.
The United Statesand Saudi Arabia have accused Iran of carrying out attacks against six oiltankers near the Strait in the past two months, a claim Tehran has denied.
The U.S. officials,who spoke on condition of anonymity, declined to quantify the extent to whichsurveillance near U.S. forces has increased in Iraq or to specify which militiawere carrying it out.
"We have seenan uptick in drone activity in Iraq near our bases and facilities," thefirst official said. "Certainly the drones that we have seen are more ofthe commercial off-the-shelf variant. So they're obviously a deniable typeUAV-activity in Iraq."
A second officialsaid the recent increase in surveillance was worrying but acknowledgedIran-linked militia in Iraq had a history of keeping tabs on Americans.
Reuters haspreviously reported that the United States has indirectly sent warnings toIran, saying any attack against U.S. forces by proxy organizations in Iraq willbe viewed by Washington as an attack by Iran itself.
In recent weeks,mortars and rockets have been fired at bases in Iraq where U.S. forces arelocated but no American troops have been injured. U.S. officials did not linkthose attacks to the increased surveillance.