(CNN) -- Mexican smugglers have used tunnels, cars, boats and even the human body in attempts to sneak drugs past U.S. agents in an endless cat-and-mouse game on the U.S.-Mexico border.
Now smugglers have devised a new invention to ferry their contraband over the nearly militarized border: cannons.
An air-powered cannon fires bags of illegal drugs into the air from Mexico and plops them on U.S. soil, for nighttime retrieval by conspirators, U.S. authorities said Thursday.
Mexican authorities recently confiscated one such cannon in the bed of a pickup truck in Mexicali, police there said. Mexicali shares the international boundary with Calexico, California.
The confiscation of the cannon -- which Mexican authorities publicized in a photograph -- is the first that U.S. border and customs agents are aware of, a U.S. official said.
"Well, I've been in (law enforcement) for over 20 years, and it seems like within the last five to 10 years they have gotten really, really creative in how they bring their drugs across," said Andy Adame, special operations supervisor for the Joint Field Command Arizona of U.S. Customs and Border Protection.
Cannons apparently are smugglers' newest creation, said Adame, who's based in Tucson.
"This is the first one that I've seen," he said Thursday of the one seized by police in Mexicali. "That was actually a pretty good one.
"They are definitely out of the ordinary," Adame said.
In another incident, U.S. authorities found 33 cans of marijuana embedded in Arizona farmland last December, as if they dropped out of the sky, Adame said.
In fact, U.S. authorities believe a pneumatic cannon fired each canister 500 feet over the Colorado River from Mexico.
American agents notified Mexican authorities to search their side of the border, U.S. Customs and Border Protection said in a statement last December.
Only a carbon dioxide tank was found, the U.S. agency said.
The 33 cans contained a total of 85 pounds of marijuana, valued at $42,500, U.S. authorities said.
"The smugglers were trying to pick these up before daylight, but there was probably an agent in the area," Adame said, explaining why the smugglers on the U.S. side never collected the canisters that pockmarked the tilled land.
Last week, police in Mexicali found a cannon made from a large tube in the back of an abandoned Dodge Ram pickup truck, said spokesman Edgar Lopez.
The device operated with a compressor connected to the truck, Mexican authorities said.
No arrests have been made.
Last year, Mexican authorities seized a catapult that was used to launch bundled drugs, Lopez said. In connection with that incident, U.S. authorities seized marijuana near Naco, Arizona, that was apparently launched over the border fence, Adame said.