The U.S. military this week used a laser to shoot down three drones along the U.S.-Mexico border that were allegedly operated by drug cartels, the Pentagon said Thursday.

The three unmanned aircraft systems were shot down late Tuesday night and early Wednesday morning using an “Army Multipurpose High Energy Laser system,” according to U.S. Northern Command, which is responsible for overseeing certain military defense operations in North America.

The drones were downed by the U.S. military’s southern border Joint Task Force, a unit of USNORTHCOM, which did not specify exactly where the drones were shot down, or which cartels they were believed to belong to. No details on the operation were provided.

Asked if the drones were shot down over U.S. or Mexican airspace, a USNORTHCOM spokesperson told CBS News that “the shots were taken in coordination with all partners operating along the border. Due to operational security reasons and ongoing counter cartel and counter drone operations, we do not have additional details to provide at this time.”

The drones were determined to be “hostile” because they were in “support of activities posing a physical threat to U.S. military personnel” and U.S. Customs and Border Protection, USNORTHCOM said.

“Cartel networks are increasingly employing unmanned aircraft systems to facilitate illicit human-smuggling and actively spy on our personnel and law enforcement partners,” Maj. Gen. Curtis Taylor, commander of the southern border’s Joint Task Force, said in a statement. “By integrating layered countermeasures alongside advanced directed-energy capabilities like this laser system, we have made it clear that we will not tolerate hostile surveillance.”

In February, a U.S. military laser accidentally shot down a U.S. Customs and Border Protection drone in the Fort Hancock area in southwest Texas.

And earlier that same month, the Federal Aviation Administration briefly shut down commercial airspace around El Paso following an internal safety disagreement between the FAA and Pentagon over military drone tests that were being conducted near Fort Bliss that sources said involved a high-energy laser system.

At the time, Transportation Secretary Sean Duffy said that the FAA and Defense Department had “acted swiftly to address a cartel drone incursion” and that the “threat has been normalized.” 

Austin Doctor, an associate professor at the University of Nebraska at Omaha and the director of strategic initiatives at the National Counterterrorism Innovation, Technology, and Education Center, told CBS News in February that the cartels primarily use drones near the border for surveillance purposes “to support their other illegal criminal activities, including smuggling of narcotics, smuggling of persons, firearms, and other illicit goods.”

Doctor noted the cartels have not used weaponized drones inside the U.S., but they do use them inside Mexico to target rival cartels. 

The southern border Joint Task Force, which has about 8,000 U.S. service members, was formed last year in support of President Trump’s immigration crackdown.