Updated

WASHINGTON -- In an effort to stem the illicit flow of weapons into Mexico, the Justice Department announced Monday that all gun shops in four Southwest border states will be required to alert the federal government to frequent buyers of high-powered rifles.

The new policy comes amid criticism of a failed federal probe aimed at dismantling large-scale arms trafficking networks along the Arizona border with Mexico.

In the probe, called Operation Fast and Furious, several agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives say they were inexplicably ordered by superiors to stop tracking some small-time "straw" buyers who purchased large numbers of weapons apparently destined for drug cartels.

Under the new policy, federal firearms licensees in Texas, California, Arizona and New Mexico must report purchases of two or more of some types of rifles by the same person in a five-day span. The requirement applies to purchases of semi-automatic rifles that have detachable magazines and a caliber of greater than .22.

ATF estimates it will generate 18,000 reports a year.

Deputy Attorney General James Cole said the new reporting measure will improve the ATF's ability to disrupt illegal weapons trafficking networks that funnel firearms to criminal organizations.

One of the critics of Operation Fast and Furious called the new policy "the height of hypocrisy."

The Obama administration is restricting the gun rights of border state citizens, "when the administration knowingly and intentionally allowed guns to be trafficked into Mexico," said House Judiciary Committee Chairman Lamar Smith, R-Texas.

"Limiting the Second Amendment rights of law-abiding citizens is not going to solve the problem," Smith said.

ATF estimates the requirement will cover nearly 8,500 gun store operators in the four states, though less than 30 percent of those operators are expected to have multiple sales to report.

ATF will retain the information and if no investigative leads have been realized after two years, it will be purged.

Holders of federal firearms licenses already report multiple sales of handguns. The results go to the National Tracing Center, and ATF says it has led to successful prosecutions for firearms trafficking.