Drug cartels are using unmanned drones to carry drugs across the southern border, challenging the U.S. technological ability to stop the advance.

Brandon Judd, an agent and president of the National Border Patrol Council, warned that the border patrol does not have the technology to contain drones.

“The number is just astronomical,” Judd told The Washington Times.

At least 13 drones believed to be carrying drugs were spotted in November alone, agents said, according to the Times. The San Diego border area has seen the most activity.

“The moment drones started becoming household items, CBP (U.S. Customs and Border Protection) should have anticipated their use for criminal enterprise,” Judd told the publication. “Instead, and in typical CBP fashion, it waited until an issue became a crisis before it chose to act.”

Defending against drones are inherently challenging and there are no policies in place, which is reportedly a source of frustration for patrol agents.

“We’re hoping that D.C. gets off the dime or starts getting ahead of the curve instead of being behind the curve, and gives us the tools to keep the country safe,” Christopher J. Harris, an agent and secretary of Local 1613 of the National Border Patrol Council told the Times.

Last year, a 25-year-old U.S. citizen was charged with using a drone to smuggle more than 13 pounds of methamphetamine from Mexico. He reportedly used drones to smuggle drugs five or six times over the period of six months, before he was arrested last year.

Rep. Vicky Hartzler, R-Mo., proposed a bill last year to expand the rules of engagement of border patrol agents with drones. The draft bill, circulated back in November, would authorize federal agencies to track and disrupt drones, in addition to seizing control or firing them down if they deemed a threat to safety.

The Associated Press contributed to this report