Republican Rep. Darrell Issa fired off a subpoena Friday to the Justice Department agency in the middle of a cross-border gun sales operation that has been blamed for a massive flow of arms to Mexican drug cartels and possibly the death of a U.S. border agent.

Issa, chairman of the House Committee on Oversight and Government Reform, demanded the Bureau of Alcohol, Tobacco, Firearms and Explosives provide him documents related to "Project Gunrunner" after the agency failed to respond to questions by a Wednesday deadline.

"The unwillingness of this administration -- most specifically the Bureau of Alcohol, Tobacco, and Firearms -- to answer questions about this deadly serious matter is deeply troubling," Issa said in a written statement. "Allegations surrounding this program are serious and the ability of the Justice Department to conduct an impartial investigation is in question. Congressional oversight is necessary to get the truth about what is really happening."

Issa first requested the documents in a March 16 letter to Acting Director Kenneth Melson. Among the paperwork, he was seeking details on Project Gunrunner, its "Fast and Furious" component in Arizona and records related to the murder of Border Patrol Agent Brian Terry, who was killed in a December 2010 shootout.

Project Gunrunner, which got under way in late 2009, allowed straw buyers to illegally buy and export guns to Mexico. The stated goal, according to ATF, was to track the flow of guns in order to bring down the entire trafficking organization. Instead, records show it allowed more than 1,700 guns, including hundreds of AK-47s and high-powered, armor-piercing .50-caliber rifles to be trafficked to Mexico.

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Whistleblowers say the guns were allowed "to walk," and ATF agents insisted federal firearms licensees participate even after they expressed grave objections to the plan.

Last week, President Obama conceded that Fast and Furious may have been "a serious mistake," but he claimed, "I did not authorize it; Eric Holder, the attorney general, did not authorize it. He's been very clear that our policy is to catch gunrunners and put them into jail."

In his statement Friday, Issa said the president did not specify whether Holder was aware of the policy or who did authorize it.

"One of the questions we always ask is who is lying," Issa told Fox News earlier this week. "We lose our credibility if we don't come clean and make the changes necessary to save lives on both sides of the border."

The subpoena orders ATF to provide documents to the committee by April 13 or face a contempt of Congress charge.

Issa's order asks for any memos, communications or other reports about the genesis of the program, any complaints or objections from agents in the field asked to operate the program or failing to track federal firearms licensees ordered to sell to straw buyers, an inspector general's report issued in November 2010 and details about individuals authorized to to "walk" guns to Mexico.

Issa also asked for papers relating to communications between ATF and the federal firearms licensee who sold weapons to Jaime Avila, who was arrested in connection with Terry's murder. Two guns found at the Terry crime scene were traced back to Avila, who was tracked by ATF but whose guns reportedly were not.

Issa said he wants information on any other weapons found at the Terry crime scene as well as communications between ATF and the special agent in charge of the Phoenix office, William D. Newell, assistant special agents in charge Jim Needles and George Gillette, group supervisor David Voth and any other case agents involved between Nov. 1, 2009, and the present.