By Ryan Gallagher, Slate

Drones in the United States are currently only authorized to be used for surveillance purposes. But that hasn't stopped the Department of Homeland Security from considering weaponizing its unmanned aircraft so they can "immobilize" targets in border areas.

Newly released documents, dated 2010, show that the DHS's Customs and Border Protection arm has weighed the possibility of adding "non-lethal weapons" to its Predator unmanned aircraft, which are currently used predominantly to monitor border zones in Arizona and Texas. The documents, obtained by the Electronic Frontier Foundation through a Freedom of Information Act request, show the CPB suggesting in a "law enforcement sensitive" report to Congress that its drones could be upgraded to include the weapons to shoot at "targets of interest." The documents do not detail specific weapons, but "non-lethal" rounds deployed on drones could feasibly include rubber bullets, tear gas, or a Taser-like shock.

That CBP has considered weaponizing its drones will add to concerns about potential mission creep with unmanned technology being used domestically. Rights groups have previously raised concerns about the possibility of drones in the United States being equipped with weapons, which may have prompted President Obama during a speech in May to state that he believed no president should "deploy armed drones over U.S. soil." The FAA, which is working to integrate drones into the national airspace system by September 2015, has said that it has rules in place that "prohibit weapons from being installed on a civil aircraft" and that it does not "have any plans on changing them for unmanned aircraft." But as drone technology is increasingly adopted by law enforcement agencies, the agency may come under pressure to rethink those regulations.

Nonlethal weapons are not the only piece of controversial kit that CBP has considered adding to its drones, either. The agency, which has 10 Predator drones equipped with sensors and day-and-night cameras, has also refused to rule out deploying eavesdropping devices on its drones to monitor phone calls and other communications on the ground below. Back in March, the agency claimed the use of such equipment would only be implemented in line with "civil rights/civil liberties and privacy interests and in a manner consistent with the law and long standing law enforcement practices."

A CBP spokesman did not respond to a series of emailed questions Wednesday regarding the potential use of weapons on its Predator fleet. EFF is calling on Congress to halt the expansion of CBP's Predator drone program and is demanding that the agency "assure the public that it will not equip its Predators with any weapons--lethal or otherwise."

