A Defense Department official said the US military found at least one instance when Afghan militants had accessed the feeds within the last several months.

The official did not confirm how many times and by which side the feeds were used, the Associated Press reported on Friday.

The military in 2008 seized an Iraqi militant who had some of the feeds on his laptop.

Discovery of more such intercepts in militant possession earlier this year raised the suspicion that the gunmen would regularly intercept the broadcasts before circulating them among other militant branches.

Prominent US dailyThe Wall Street Journal quoted an unnamed source as saying that the military had found “days and days and hours and hours of proof” of the infiltration.

The defense manufacturers would reportedly fail to close a loophole in the communications by leaving the signal path from the aircraft to the ground control unencrypted. Militants would access the downlink, using cheap computer software.

The US government reportedly refused to eliminate the flaw for more than a decade, confident that it would not be taken advantage of.

The aircraft have been carrying missile strikes on alleged militant hideouts on the Pakistani tribal regions for over two years and are currently engaged in their “heaviest ever” round of attacks there.

Reports by the Pakistani media outlets, however, point out that the raids have mostly killed civilians. Since August 2008, at least 628 people have been killed in 66 such strikes.

Local officials commenting on the incidents involving the planes often ask not to be named, citing the “sensitivity” of the attacks carried out by the US Central Intelligence Agency (CIA) in cooperation with the Pentagon.

The drones are also used in Iraq, Afghanistan and Somalia and the military plans to usher in more advanced ones ranging from pilotless aerial vehicles and miniature drones to huge bomber drones fitted with nuclear armaments.