WASHINGTON - The federal government under the Bush administration ran an operation that allowed hundreds of guns to be transferred to suspected arms traffickers - the same tactic that congressional Republicans have criticized President Barack Obama's administration for using, two federal law-enforcement officials said Tuesday.

Rep. Darrell Issa of California, Sen. Chuck Grassley of Iowa and other Republicans have been hammering the Obama Justice Department over the practice known as "letting guns walk." The congressional target has been Operation Fast and Furious, which was designed to track small-time gun buyers at Phoenix-area gun shops up the chain to make cases against major weapons traffickers. In the process, agents lost track of many of the more than 2,000 guns.

When George W. Bush, a Republican, was president, the Bureau of Alcohol, Tobacco, Firearms and Explosives in Tucson, used a similar enforcement tactic in a program called Operation Wide Receiver. The fact that there were two such ATF investigations years apart in separate administrations raises the possibility that agents in still other cases may have allowed guns to "walk."

Federal law-enforcement officials familiar with the matter say Operation Wide Receiver began in 2006 after the agency received information about a suspicious purchase of firearms. The investigation concluded in 2007 without any charges being filed.

After Obama took office, the Justice Department reviewed Wide Receiver and discovered that ATF had permitted guns to be transferred to suspected gun traffickers, according to the officials, who spoke on condition of anonymity because the practice is under investigation by Congress and the Justice Department's Inspector General's Office.

Following the discovery that agents in Tucson let the guns "walk," a tactic which has long been against Justice Department policy, the department under Obama decided to bring charges against those who had come under investigation in 2006.

To date in Wide Receiver, nine people have been charged with making false statements in acquisition of firearms and illicit transfer, shipment or delivery of firearms. Two of the nine defendants have pleaded guilty and a plea hearing is scheduled for Oct. 13 for two other defendants.