The Central Intelligence Agency (CIA) has been conducting surveillance flights with drones over Mexico in partnership with the U.S. neighbor to the south, to gather intelligence on cartels and fentanyl laboratories, according to a senior U.S. official.

The Biden administration authorized the use of MQ9 Reaper drones, which the official said are not armed and “not lethal,” over Mexico to focus on locating fentanyl labs and cartels.

President Donald Trump’s administration continued the program, which is being done in coordination with the Mexican government.

The intelligence is shared with the Mexican government, which in turn has the authority to act on shutting down any illegal activities associated with the cartels and labs.

Hundreds of pounds of fentanyl and meth seized near Ensenada in October arrive for officials from Mexicos attorney generals office to be unloaded at their headquarter in Tijuana, Mexico, Tuesday, October 18, 2022. (Salwan Georges/The Washington Post via Getty Images)

He was apparently referring to thousands of drug labs detected in previous years in the hills and scrublands around Culiacan, the capital of the northern state of Sinaloa. Those clandestine, rural production sites were often bare-bones, improvised labs covered with tree branches and tarpaulins.

Now, the meth trade has become so lucrative and so sophisticated that Mexican meth is exported as far away as Hong Kong or Australia, and the cartels have found ways to avoid detection of their drug money.

Fentanyl production is also huge, though because it is a more potent drug, the volume is smaller.

Soldiers seized more than a half-million fentanyl pills in Culiacan in 2023, in what the army at the time described as the largest synthetic drug lab found to date.

Soldiers found almost 630,000 pills that appeared to contain fentanyl, the army said. They also reported seizing 282 pounds of powdered fentanyl and about 220 pounds of suspected methamphetamine.

The Associated Press contributed to this report.