Does the US supply 90% of weapons?

There's a claim floating around that 90% of weapons used in crimes in Mexico have been traced to the US. It turns out the right number is actually lower than 20%.

The fact is, only 17 percent of guns found at Mexican crime scenes have been traced to the U.S.

What's true, an ATF spokeswoman told FOXNews.com, in a clarification of the statistic used by her own agency's assistant director, "is that over 90 percent of the traced firearms originate from the U.S."

But a large percentage of the guns recovered in Mexico do not get sent back to the U.S. for tracing, because it is obvious from their markings that they do not come from the U.S.

The exaggeration of United States "responsibility" for the lawlessness in Mexico extends even beyond the "90-percent" falsehood -- and some Second Amendment activists believe it's designed to promote more restrictive gun-control laws in the U.S.

In a remarkable claim, Auturo Sarukhan, the Mexican ambassador to the U.S., said Mexico seizes 2,000 guns a day from the United States -- 730,000 a year. That's a far cry from the official statistic from the Mexican attorney general's office, which says Mexico seized 29,000 weapons in all of 2007 and 2008.

Chris Cox, spokesman for the National Rifle Association, blames the media and anti-gun politicians in the U.S. for misrepresenting where Mexican weapons come from.

"Reporter after politician after news anchor just disregards the truth on this," Cox said. "The numbers are intentionally used to weaken the Second Amendment."

"The predominant source of guns in Mexico is Central and South America. You also have Russian, Chinese and Israeli guns. It's estimated that over 100,000 soldiers deserted the army to work for the drug cartels, and that ignores all the police. How many of them took their weapons with them?"