Arms trafficking from within the United States, long thought to be relegated to gun-running for Mexican drug cartels, is far more extensive than previously thought, according to a new report by a weapons research group released Wednesday.

The report, published by the Geneva-based Small Arms Survey, examines more than 150 court cases involving arms trafficking from within the United States from 2010-2015. Spanning 46 countries and six continents, the report details elements of a smuggling network that has managed to supply weapons to a range of recipients — from Honduran farm workers to a Finnish motorcycle gang.

While numerous cases involved the shipment of weapons and their parts to different areas of the globe, the majority — 84 of the 159 — involved smuggling weapons to Mexico, according to the report. Of those 84, nearly half involved the illegal shipment of rifles. Mexico has long been the site of illegal U.S. arms shipments. Mexico’s porous, rugged border and burgeoning population of drug cartels has turned the United States’ southern neighbor into a hub of illicit arms.

An additional wrinkle to illegal arms trafficking within the United States is the shipment of weapons’ parts both to Mexico and elsewhere around the world. More than half of the report’s cases involve the shipment of disassembled firearms parts, such as the upper halves of rifles, known as upper receivers, and rifle barrels. Twenty-one of the cases involved the shipment of only rifle parts.

In one example detailed in the report, traffickers based in the Philippines and the United States ordered weapons’ parts over the Internet to an address in the United States. From there, the parts — approximately $200,000 in “defense items” including 5.56 mm rifle components — were repackaged and sent to the Philippines. This lasted from 2008 to 2013 when the smuggling ring was broken up by a series of arrests. According to the report, this method has been repeated across the country in states, such New Jersey and Oregon, and in Washington, D.C.

A smuggling network in California, for example, sent 240 shipments — worth more than $1 million — of rifle and pistol components to Thailand before being caught by law enforcement officials. In Texas, individuals bought rifle components, and using commercially available equipment, home-built 900 Kalashnikov-style rifles before sending them into Mexico.

Unlike drugs that can be shipped covertly in small quantities, moving weapons around the world takes some ingenuity. For weapons illegally shipped to Mexico, according to the report, the guns were mostly sent either on foot or hidden in vehicles. In some instances, the weapons were duct-taped around a smuggler’s body. Additionally, many of the vehicles responsible for smuggling weapons and ammunition had modified panels that had been repurposed to hide the illicit arms.

For weapon shipments sent outside of Mexico, smugglers employed a range of methods. In 20 of the documented cases, traffickers used maritime shipping containers to get weapons abroad. Other methods included shipping parts in padded envelopes delivered by the U.S. Postal Service, and smuggled aboard commercial aircraft. In some cases, according to the report, a number of weapons sent through the mail were done so with false shipping documents. The weapons, in some of these cases, were identified as “metal hunting tools” and “toy parts.”

According to the report, eight cases involved smugglers flying to foreign countries with “firearms and related items” hidden in their luggage. In one of the documented cases, a trafficker from North Carolina smuggled 63 weapons to Britain on nine different flights in 2010. During one flight, according to the report, the smuggler was questioned after a Transportation Security Administration officer found one of the shipments. The trafficker said he was a salesman traveling from a gun show and that the weapons were not in working order. The TSA officer let the smuggler continue on to Britain.

According to Matt Schroeder, a senior researcher at the Small Arms Survey and the author of the report, his research highlights how complex arms trafficking actually is compared with what might be assumed. Stopping it, he said, “will require the cooperation of many actors both public and private.”