The sudden closure of airspace over El Paso, Texas, sowed chaos and confusion. The Federal Aviation Administration announced a 10-day suspension of flights, only to reverse itself within hours, as claims circulated that drug cartel-controlled drones had crossed the border from Mexico. The episode forced US security officials to confront a threat they appeared unprepared to handle.

The exact reasons for suspending all flights over a major American city remain contested. The White House and Pentagon insisted that drug cartel drones prompted the closure. Meanwhile, various media outlets cited sources saying the military’s use of anti-drone technology prompted the sudden shutdown. CBS News reported that the Pentagon was planning to test high-energy lasers at Fort Bliss in El Paso. A previous test last week targeted a foreign drone, but shot down a party balloon instead.

The closure of airspace over El Paso has once again highlighted the vexing problem of Mexican drug cartels using drones to breach the US border. The temporary shutdown comes as cartels increasingly deploy drones for aerial attacks on rivals in Mexico’s most violent regions, borrowing tactics honed in Ukraine’s defense of its territory — with expertise reportedly provided by former Colombian special forces, according to The Wall Street Journal.

US Northern Command’s top general has estimated more than 1,000 unmanned aircraft system incursions cross the US border from Mexico each month. Cartel-operated drones track smuggling routes and ferry fentanyl across remote stretches of the border, dropping payloads in isolated desert terrain. They also surveil US Border Patrol movements, enabling traffickers to move drugs and migrants across the frontier with greater precision.

“For us who live and work along the border, this is every day for us,” Rep Tony Gonzáles told KTSM TV. “We, the federal government, the military, CBP is working on combating that, but we have a long way to go.”

The constant flow of drones underscores the grip drug cartels hold over Mexico’s border cities. That control has become so suffocating that migrants in Tamaulipas — including Nuevo Laredo, Reynosa and Matamoros — opposite Laredo, McAllen and Brownsville respectively, report being forced to pay protection money simply to access the region, and again for permission to illegally cross the Rio Grande.

Migrant crossings have fallen sharply during the first year of the Trump administration as Mexico stepped up enforcement, responding to pressure that was first applied in the final year of the Biden presidency. Drones, however, continue to be used to smuggle drugs such as fentanyl into the United States, according to US officials.

Mexico’s president, Claudia Sheinbaum, said on Wednesday that she had no prior knowledge of the Federal Aviation Administration’s actions in El Paso. While downplaying the security situation in Mexico, she reiterated her standard call for greater bilateral coordination. “If the FAA or any other US government agency has information,” she said, “they can ask the Mexican government.”

Since Trump returned to office, Mexico has increased cooperation against drug cartels. Sheinbaum’s government has extradited more than 90 alleged cartel leaders to the United States, restored cooperation with the Drug Enforcement Administration after it deteriorated under her predecessor, Andrés Manuel López Obrador, and intensified operations against the Sinaloa Cartel, one of the world’s leading producers of fentanyl, according to the DEA.

Despite a fall in homicides during Sheinbaum’s first 14 months in office, battles still rage in parts of the country such as the western state of Michoacán — home to lucrative avocado and lime groves — where drug cartels have deployed drones, dropping increasingly sophisticated weapons and IEDs on rivals. The cartels have deployed homemade mines, too.

“It’s a terrible situation,” said Father Andrés Larios, a Catholic priest in the scorching Tierra Caliente region of Michoacán, where cartel turf wars are raging. “These drones and minefields are killing many innocent people.”