The U.S. agency that monitors gun sales has suffered a setback in its effort to increase scrutiny of the bulk sale of high-powered assault rifles in border-state gun shops that are a chief source of weapons smuggling into Mexico.

The Bureau of Alcohol, Tobacco, Firearms and Explosives wants to require gun dealers in California, Arizona, New Mexico and Texas to report the sales of two or more rifles to the same customer within a five-day period, similar to a rule that exists for handgun sales. The goal of the plan is to crack down on problem gun dealers and buyers at a time of heightened drug cartel violence along the border.

The agency asked the White House for an emergency order that would allow ATF to quickly impose the requirement without public review. But the White House denied the request and told the agency that the proposal has to undergo a standard three-month review period that is open to public comment.

The plan could still be implemented, but not on the expedited timetable that the agency had wanted.