The Department of Homeland Security and the FBI identified this week unmanned aerial systems, or drones, as one of the greatest national security threats to America — rating it as severe a concern as cybersecurity hacks, critical infrastructure attacks, and terrorism.

While drones are often thought of as techie toys, officials are becoming increasingly worried about the threat they pose and are warning it's only a matter of time until the devices are used to drop a bomb or fentanyl powder on people in a populated area. Drones are already used by transnational criminal syndicates and drug cartels. The technology is readily available to terrorist groups.

Incidents that have gained public attention in recent years have largely involved inexperienced fliers losing control of the aircraft, but the military and law enforcement officers are already dealing with cases of drones being used for illicit purposes.

Border Patrol agents and port officers belonging to the Department of Homeland Security’s U.S. Customs and Border Protection agency are dealing with drones being used as airborne spies.

[Related: Congress authorizes feds to 'disrupt' drones, worrying civil libertarians]

On the U.S.-Mexico border, drones are already being used to spy on federal law enforcement operations and smuggle contraband through the sky. The first drug smuggling incident via drone was documented in Nov. 2015. Now, it's a daily occurrence in some regions of the southern border, but it's rarely reported because CBP is unable to seize the devices. Arrests are rare.

A CBP spokesman told the Washington Examiner that Border Patrol agents based in California’s San Diego sector frequently see drones fly over the international boundary. The drones, which range from a few ounces to a few pounds, take off from Mexico’s Baja California state and buzz over agents stationed near the border at up to 50 miles per hour. The cover of darkness and the high speeds the drones can fly at make it nearly impossible for agents to shoot them down, even if they were allowed to use their firearms.

In January 2015, a drunken government employee flew a drone over the White House grounds. The incident was followed by others in May and October the same year prompting government and private-sector officials to move to protect vulnerable places from the new drone threat. Also in 2015, a drone crashed while flying over a college football game at the University of Kentucky. Those now seem like innocent days.

Drug and human smugglers are using the devices to spy on official ports of entry where CBP field officers screen passenger vehicles and tractor-trailer trucks attempting to enter the country. The devices will hover overhead and watch officers who must continue about their jobs powerless to stop the activity because existing federal law does not allow them to do anything about it.

Air and Marine Operations officers who monitor the border face challenges while flying helicopters at low altitudes. Drones can fly up to 1,000 feet in the air. Criminal controllers will often cut off their GPS trackers so helicopters cannot detect them. AMO counted 36 drone sightings in the first six months of fiscal 2018, from Sept. 30, 2017 through March 26. Of those three dozen incidents, only one drone operator was arrested. CBP was not able to provide the total number of drone sightings in fiscal 2018 on such short notice.

The National Football League's top security official is just as worried about drones as the federal government. Cathy Lanier, the former chief of police in Washington, D.C.,-turned-NFL vice president of security, testified before the Senate in September the league documented just shy of a dozen drone incidents in 2018 — none of which turned out to be deadly.

Fighting back is difficult, since any item falling out of the sky — especially one with spinning wings — can pose a threat to the public. That means it's not always possible to simply shoot them down.

But Lanier has the same problem as the federal government. She said under the Federal Aviation Administration Reauthorization Act, which was passed two weeks after her testimony, federal, state, and local law enforcement can take down a drone, but virtually all of the ways they could take that drone down are still illegal. The law bans the use of products that would rely on telecommunication networks to force the drone to return to its operator — that's because those mega-corporations have told Congress not to change current policy in a way that would affect their airwaves.

Andy Morabe is director of business development for IXI Technology, a company that has the Drone Killer device in the counter drone marketplace. The device overpowers the drone's frequency and sends it new instructions. It's very similar to a gun and has a trigger that the user can pull to kill the drone.

"You can bring down drones, but you can’t interfere with the spectrum, so that's still going to interfere their ability to use ours, Drone Killer, Drone Buster, and others," said Morabe. "You're almost powerless. There are a few net guns. It looks like a Bazooka, I think it’s called the SkyWall, and it shoots a net at the drone. So you’re limited in range, you’re limited in visibility, and you can only have one."

He said local law enforcement offices are constantly inquiring about his company's machine even though it's illegal for them to purchase and use.

Morabe and Lanier echoed the same concern: The FAA bill doesn’t go far enough in allowing DHS and local law enforcement to mitigate drones that pose a threat. And they're being forced to consider items like Drone Killer, which is illegal for local officials to use but could save lives if it prevented a drone from dropping biological or chemical weapons in public.

"Several stadium security directors have told me that they are regularly approached by vendors selling drone countermeasure equipment. The vendors acknowledge, and the security directors readily know, that using such devices is illegal. The current state of the law, however, leaves security officials with an unenviable choice: Procure equipment whose use would be illegal, or remain unequipped to respond to a security threat that could endanger tens of thousands of people," Lanier said, according to her prepared remarks.

Morabe said it's not a matter of lawmakers not wanting to act but that they are tied to donations from the telecommunications industry, which is adamantly opposed to counter-drone machines because it would rely on their networks to send a signal to the drone as it jams the drone's mission instructions.

"In recent conversations, lawmakers of both parties have said that it’s because it's a powerful lobbying group — the telecommunications industry — that it would take another terrible act of 9/11 with a drone to force Congress to make the changes right away," said Morabe.

"We give officers guns with bullets. If they make life and death decisions all the time and we trust them with that, why can't they apply the same training and rules of engagement with this device?" he said.