"The drones are a big deal, one of the most significant threats our troops there face", former Central Intelligence Agency (CIA) officer Michael P. Mulroy said as quoted by the newspaper on Friday.
According to the US officials speaking to the newspaper, at least three times in the past two months, small, explosive drones have been deployed to crash into targets on Iraqi bases late at night. The attacked bases include those housing CIA and US Special Operations units.
Three US officials familiar with the matter told the news outlet that the drones used in the attacks had been partially recovered, and analyses showed that they were "produced in Iran or with technology provided by Iran".
As the newspaper alleges, Iran is using its forces to put pressure on the United States in the region in hopes that the US will lift off economic sanctions placed on the country as part of the 2015 nuclear deal, where Iran had agreed to limit its nuclear activities in exchange for the lifting of the economic sanctions imposed on the country.