Mexican police have confiscated an improvised cannon that they say was used to fire packages of marijuana across a border fence into California.

The makeshift cannon was made of plastic pipe and powered by compressed air sourced from an old car engine, police in the border city of Mexicali said. The device was able to fire cylinders packed with up to 30 pounds of pot.

The cannon was discovered on Tuesday after U.S. officers told Mexican police that they had been confiscating a large number of drug packages that appeared to have been fired over the border, the Associated Press said.

It's not the first time drug traffickers have used a cannon to transport marijuana across the border. In December, U.S. Customs and Border Protection officials recovered more than 30 cans of marijuana scattered in Yuma, Ariz., near the Colorado River.

According to NBC, an investigation of the area "determined that the cans were fired from about 500 feet away with a pneumatic-powered cannon" and that a "carbon-dioxide tank was found nearby."

In that case, the cannon was not found. But Mexican border police said on Tuesday that they have confiscated similar devices in recent years.