U.S. gun stores and gun shows are the source of more than 90 percent of the weapons being used by Mexico's ruthless drug cartels, according to U.S. and Mexican law enforcement officials.
"It's a war going on in Mexico, and these types of firearms are the weapons of war for them," said Bill Newell, the special agent in charge of the Phoenix field division of the ATF, the Bureau of Alcohol, Tobacco, Firearms and Explosives, which has primary law enforcement jurisdiction for investigating gun trafficking to Mexico.
"It's virtually impossible to buy a firearm in Mexico as a private citizen, so this country is where they come," said Newell.
But U.S. efforts to stop the smuggling of tens of thousands of guns to Mexico, including high-powered assault weapons, have been hampered by lenient American gun laws and the Bush administration's failure to give priority to anti-gun smuggling efforts, officials tell ABC News for a report Tuesday on ABC News' "World News With Charles Gibson."
President Bush said today at a press conference that Mexican President Felipe Calderon again raised the issue of guns at their meeting in New Orleans.
Mexico's strict gun laws are being subverted by the easy availability of weapons in the U.S., the Mexican attorney general, Eduardo Medina-Mora Icaza, told ABC News. "The Second Amendment," said the attorney general, "is certainly not designed to arm and give fire power to organized crime abroad."
More than 3,400 people have been killed by the drug cartels in the last 15 months, 2,000 of them law enforcement officials, according to the Mexican attorney general.
U.S. and Mexican officials say they have traced most of the thousands of high-powered weapons seized from the drug cartels to gun dealers in Texas, California and Arizona.
Assault weapons made in China and Eastern Europe, resembling the AK-47, have become widely and cheaply available in the U.S. since Congress and the Bush administration refused to extend a ban on such weapons in 2004.
Under federal gun laws, gun dealers are not required to report multiple purchases of such weapons because they are classified as rifles.
"If you were to go into a gun store and buy 20 of these, there is no requirement by the gun dealer to fill out a multiple sales form," said the ATF's Newell.
The drug cartels' weapons of choice include variants of the AK-47, .50-caliber sniper rifles and a Belgian-made pistol called the "cop killer" or "mata policia" because of its ability to pierce a bulletproof vest.
"It's in high demand by your violent drug cartels, their assassins in Mexico," said Newell of the ATF. The gun can fire a high-powered round used in a rifle.
An ABC News investigation found the "mata policia" and a wide range of assault weapons prominently displayed at gun stores along the border in Texas, the state providing the most weapons to the drug cartels, according to the ATF.
Under Texas and federal law, there is no waiting period for the purchase of such weapons and no restriction on how many can be bought at a time.
U.S. officials say there is little they can do to go after licensed gun dealers because large purchases, dozens or hundreds at a time, are legal for U.S. citizens and legal immigrants with an INS green card unless a gun dealer suspects the purchase is being made for someone else.
ATF agents say legitimate gun dealers will often report suspicious activities, but that a small but significant number looks the other way.