In prepared testimony before the House Oversight and Government Reform Committee, led by Rep. Darrell Issa, R-Calif., Holder said "allowing guns to 'walk' -- whether in this administration or in the prior one -- is wholly unacceptable."
"This tactic of not interdicting weapons, despite having the ability and legal authority to do so, appears to have been adopted in a misguided effort to stem the alarming number of illegal firearms that are trafficked each year from the United States to Mexico," Holder said. "To be sure, stopping this dangerous flow of weapons is a laudable -- and critical -- goal. But attempting to achieve it by using such inappropriate tactics is neither acceptable nor excusable."
Issa earlier threatened Holder with contempt of Congress if the Justice Department failed to deliver documents by a deadline next week, CNN reported.
In an exchange that began Tuesday, Issa criticized the Justice Department for releasing long-sought documents -- after close-of-business Friday -- that revealed Assistant Attorney General Lanny Breuer discussed with Mexican officials a plan that would allow illegal guns "to walk" into Mexico where Mexican officials would arrest gun-runners.
In an e-mail, Issa said the Feb. 4, 2011, communication indicated "Breuer suggested allowing straw purchasers cross in Mexico" so Mexican officials could "arrest, prosecute and convict" on the same day Assistant Attorney General Ronald Weich "wrote to Congress denying that the department allowed guns to walk."
The Justice Department Wednesday said Issa's letter indicated a "significant misunderstanding both of the documents we recently produced and of the department's position on the issues you raise."
"When I learned early last year about the allegations raised by ATF agents involved with Fast and Furious, I took action," Holder said in his Thursday testimony. "In addition to requesting an inspector general investigation last February, I ordered that a directive be sent prohibiting the use of such tactics. There also have been important personnel changes in the department. And vital reforms reflecting the lessons we have learned from Operation Fast and Furious have been implemented.
"Today, I reaffirm my commitment to ensuring that these flawed tactics are never used again. And I reiterate my willingness to work with Congress to address the public safety and national security crisis along our southwest border that has taken far too many lives. …
"The Department of Justice stands ready to work with you -- not only to correct the mistakes of the past, but also to strengthen our law enforcement capacity in the future," Holder concluded.
Republicans want to learn whether officials in President Barack Obama's administration knew of the controversial tactics, but so far Breuer is the highest-ranking official known to be aware of the sting. The political set-to has been going on for more than a year following the discovery that two of the "Fast and Furious" weapons that had gone missing in Mexico were found in Arizona at the scene of the killing of U.S. Border Patrol agent Brian Terry.
In his letter to Holder Issa said, "If the Department continues to obstruct the congressional inquiry by not providing documents and information, this committee will have no alternative but to move forward with proceedings to hold you in contempt of Congress."
In the department's response, Deputy Attorney General James Cole said the Feb. 9 deadline was "impossible" because of the breadth of the request, The Washington Post reported.
The hearing featured tense exchanges between Holder and several Republican committee members, including Rep. Ann Marie Buerkle of New York, who asked the attorney general, "How many more Border Patrol agents would have had to die as part of Operation Fast and Furious for you to take responsibility?" -- a reference to agent Brian Terry, who critics of the program say was killed because of it, The Hill reported.
"That kind of question I think is frankly, and again respectfully, and I think -- is beneath a member of Congress," Holder said.
Rep. Raul Labrador, R-Idaho, displayed quotations from Holder's responses in 2001 to questions in Congress about a controversial pardon granted by President Bill Clinton. Holder said at the time he was not familiar with all documents in the pardon matter and Labrador called that evidence of a "pattern" of incompetence.
Holder called Labrador's line of question "among the worst things I think I've ever seen in Congress."
"Have I been perfect? No," Holder said. "Have I made mistakes? Yes. Do I treat the members of this committee with respect? I always hope that I do. And what you have just done is, if nothing else, disrespectful, and if you don't like me, that's one thing, but you should respect the fact that I hold an office that is deserving of respect. Maybe you're new to this committee; I don't know how long you've been here. But my hope would be that we can get beyond that kind of interaction, that kind of treatment of a witness."
Rep. Dan Burton, R-Ind., accused the Justice Department of hiding information from the committee and urged Issa to take steps to issue a contempt citation if Holder doesn't give the committee all the documents it has demanded, The Hill reported.