United States border agents are cracking down on gun trafficking across the southern border as part of a broader bilateral effort against Mexican drug cartels. 

U.S. Customs and Border Protection reported intercepting 1,171 guns before they crossed into Mexico in 2023. That is nearly seven times as many as in 2019, when CBP intercepted 173 guns. 

While experts say the increase is promising, the number of weapons being captured by CBP still represents only a sliver of the hundreds of thousands of guns that researchers estimate are trafficked from the United States to Mexico every year. 

“It’s a symbolic gesture that the U.S. is taking this concern seriously,” David Shirk, a political science professor at the University of San Diego who specializes in U.S.-Mexico relations, told The Trace. “I say ‘symbolic’ because a thousand guns isn’t that many guns. It’s a fragment of the guns that are making their way into Mexico.”  

These guns have bolstered the cartels that U.S. authorities blame for a surge in American overdose deaths. In 2023, the United States suffered more than 112,000 fatal drug overdoses for the first time ever. The majority of those deaths involved fentanyl and other synthetic opioids, much of which is synthesized in Mexico before being smuggled over the border. 

A 2023 audit conducted by the U.S. Government Accountability Office on American security aid to Mexico concluded that “U.S. firearms trafficked into Mexico, along with the U.S.’s high demand for illegal drugs, contribute to security and drug crises on both sides of the border.”  

CBP and the White House did not respond to requests for comment. 

Alejandro Celorio Alcántara, a legal adviser for Mexico’s Foreign Ministry, said the Mexican government has long pushed the United States to prioritize tackling gun trafficking at the border. Referring to the increase in CBP seizures, he said, “I don’t think they are doing this just because Mexicans asked them. They see this as important for Americans.” 

Many of last year’s seizures involved assault-style rifles, which U.S. authorities have said are among the cartels’ “weapons of choice.” In March 2023, border agents found 34 guns, including AR- and AK-type rifles, concealed in a utility trailer trying to cross into Mexico via a bridge in Eagle Pass, Texas. Five months later, in a remote area near the Rio Grande, agents turned up two AR-15 rifles in a ranch house that had been abandoned by four people seen fleeing into Mexico when law enforcement arrived. 

Data from the the Bureau of Alcohol, Tobacco, Firearms and Explosives indicates that between 2017 and 2022, nearly 124,000 guns were recovered at crime scenes in Mexico and subsequently traced. Sixty-eight percent of those guns — more than 83,000 — came from the United States.  

Under a security agreement forged by the Biden and López Obrador administrations, Mexico has committed to tackling fentanyl laboratories operating on its soil. Meanwhile, the United States has vowed to do more to disrupt the flow of weapons to drug cartels, a promise that has ratcheted up federal efforts to target people who buy guns illegally and to intercept weapons moving through ports of entry.  

 “We are now seeing the result of a five-year effort of putting the topic on the table consistently,” Celorio Alcántara said.