National Guard troops operating a remote video surveillance system on Friday evening saw several people using the device beside a border fence near the town of Naco, and Border Patrol agents contacted Mexican authorities, NBC station KVOA of Tucson reported, citing U.S. Customs and Border Protection.
Mexican authorities disrupted the operation, but the alleged smugglers fled the scene in a Humvee and an SUV, leaving the catapult behind — along with 45 pounds of marijuana and an SUV.
Night-vision video taken by the National Guard and supplied by KVOA shows several men preparing the catapult and launching packages before fleeing.
Still images taken at the scene shows soldiers testing the catapult, which was powered with elastic and was brought in mounted on a trailer. It's not clear from the video whether they are Mexican or U.S. troops.
"I have not seen anything like that in my time before as a Border Patrol agent ... although we are trained to handle any kind of a threat that comes over that border," Tucson sector Border Patrol spokesman David Jimarez told Reuters.
U.S. authorities said the dismantling of the operation was an example of close cooperation between American and Mexican agencies.
Naco is in Cochise County, about 80 miles southeast of Tucson.
The Mexican government declared war against drug smugglers in 2006, and the resulting conflict has left more than 30,000 people dead.
The crackdown has pushed smugglers into ever-more daring and ingenious attempts to move drugs into the United States.
One technique involves the use of specially designed trucks with ramps built in the back and front. These trucks pull up next to the barbed-wire border fence and lower one of the ramps over to the U.S. side, while the other ramp slides down the back of the vehicle. Smugglers in SUVs loaded with drugs then drive across these mobile truck-bridges into Arizona without ever touching the fence.
Ultralight planes have been used by daring pilots to fly over the fence to drop drug loads on the U.S. side.
And huge tunnel systems have been uncovered in the past few months connecting San Diego's Otay Mesa industrial area with Tijuana, Mexico, producing some of the largest marijuana seizures ever in the United States.
The drug war has another connection to the U.S.: Huge amounts of weapons are being bought in border states and shipping to drug cartels, American and Mexican officials say.