WASHINGTON — President Obama on Wednesday invoked executive privilege to withhold from a Congressional oversight committee some documents and communications among his advisers regarding the failed gun enforcement operation known as “Fast and Furious,” in which weapons purchased in the United States were allowed to cross into Mexico.

It was the first time since Mr. Obama took office that he has asserted the privilege, and it sharpened considerably the long-festering dispute between Attorney General Eric H. Holder Jr. and Representative Darrell Issa of California, the Republican chairman of the House Committee on Oversight and Government Reform. The panel had been threatening to find Mr. Holder in contempt for refusing to hand over some documents.
Deputy Attorney General James Cole said in a letter to Mr. Issa that the president was claiming privilege over the documents, although he suggested that there might yet be a way to negotiate the release of some of the contested documents.
“We regret that we have arrived at this point, after the many steps we have taken to address the committee’s concerns and to accommodate the committee’s legitimate oversight interests regarding Operation Fast and Furious,” the Justice Department letter said. “Although we are deeply disappointed that the committee appears intent on proceeding with a contempt vote, the department remains willing to work with the committee to reach a mutually satisfactory resolution of the outstanding issues.”
But Mr. Issa said that the House had received no letter from Mr. Obama himself or a log specifying what was being withheld. He also raised doubts about whether executive privilege covered internal deliberative documents that did not relate to confidential communications involving the president himself.
“Our purpose has never been to hold the attorney general in contempt,” Mr. Issa said. “Our purpose has always been to get the information the committee needs to complete its work — that it is not only entitled to, but obligated to do.”
Democrats said the committee should delay its vote to consider the assertion of executive privilege and whether to challenge it in court. They accused Republicans of being intent on citing Mr. Holder with contempt in order to inflict political damage during the run-up to the presidential election.
“I treat assertions of executive privilege very seriously, and I believe they should be used only sparingly,” said Representative Elijah E. Cummings of Maryland, the panel's ranking Democrat. “In this case, it seems clear that the administration was forced into this position by the committee’s unreasonable insistence on pressing forward with contempt despite the attorney general’s good faith offer.”
Because Republicans hold a majority in the House and on the oversight committee, it appeared likely that the committee would vote to recommend holding Mr. Holder in contempt. Such a vote would place before Speaker of the House John A. Boehner, Republican of Ohio, the choice of whether or when to bring up the proposal for a vote in the full House of Representatives.
On Wednesday, Mr. Boehner's office immediately denounced the president’s action.
“Until now, everyone believed that the decisions regarding Fast and Furious were confined to the Department of Justice. The White House decision to invoke executive privilege implies that White House officials were either involved in the Fast and Furious operation or the cover-up that followed," said Michael Steel, the spokesman for House Speaker John Boehner of Ohio."The administration has always insisted that wasn’t the case. Were they lying, or are they now bending the law to hide the truth?”
Democrats argued that Republicans were rushing to do something unprecedented in American history: citing the highest law enforcement official in the land for contempt. (In 1998, the Republican-led oversight committee voted to recommend holding Attorney General Janet Reno in contempt over documents related to the impeachment of President Bill Clinton, but the measure was never put before the full House for a vote.) But Republicans said Mr. Holder had no legal right to withhold the documents, and they needed the information to complete the investigation.
But Representative Carolyn Maloney, Democrat of New York, said the investigation had degenerated into a “political witch hunt,” while a fellow Democrat, Representative Gerald E. Connolly of Virginia, called the proceeding a “kangaroo court,” saying it was designed to result in a contempt citation from the start as a way to get at Mr. Obama. They and other Democrats complained that the panel was ignoring its mission of coming up with reforms, like finding ways to strength laws to combat gun trafficking along the Southwestern border.
Republicans and Democrats had also clashed over a meeting on Tuesday when Mr. Holder met lawmakers. Mr. Issa attended along with Mr. Cummings and the top Republican and Democrat on the Senate Judiciary Committee, Charles E. Grassley of Iowa and Patrick J. Leahy of Vermont. At that meeting, in an effort to avert the contempt vote, Mr. Holder had offered to turn over some of the documents over which Mr. Obama asserted executive privilege the next day.
Mr. Issa said that Mr. Holder had offered the information on the condition that he agree to end the investigation even before he saw the documents. But Mr. Cummings said that Mr. Holder had not asked for an end to the entire investigation, but instead requested that Mr. Issa agree to bring the fight over a contempt citation to a close.
The White House said that Mr. Obama had gone longer than any president in the past three decades without asserting such a privilege in a dispute with Congress.
President George W. Bush claimed the privilege six times and President Clinton 14 times, the White House said. In both cases, they acted to withhold the same type of documents that Mr. Obama is refusing to hand over. Presidents have asserted the privilege 24 times since the Reagan presidency, the White House said.
Fast and Furious was an investigation by the Bureau of Alcohol, Tobacco, Firearms and Explosives into a gun-trafficking network that was funneling weapons purchased by “straw buyers” to a Mexican gun cartel. It ran from late 2009 to early 2011.
Agents used the tactic known as “gun walking” — failing to interdict weapons as soon as possible, in an attempt to build a bigger case. As a result, they lost track of some 2,000 weapons, two of which were later recovered at the scene where a Border Patrol agent, Brian Terry, was killed in a shootout in December 2010.
The Justice Department has turned over about 7,600 documents to Congress in response to the Congressional investigation, covering both Fast and Furious and several previous operations during the Bush administration in which the same A.T.F. division had used similar tactics.
The documents still in dispute are internal e-mails by department officials after Feb. 4, 2011, related to the Congressional investigation into Fast and Furious. That was the date that the department sent a letter to Congress in response to early questions about Fastand Furious claiming that the A.T.F. always made every effort to interdict illegally purchased guns.
As 2011 unfolded, however, the department walked back from that initial denial. Mr. Holder began an inspector general investigation into the matter, and in December the department rescinded the letter and acknowledged that it had been misleading. At the same time, it turned over internal communications leading up to the letter showing that at the time officials at Justice Department headquarters drafted it, Arizona-based law enforcement officials were insisting internally that there had been no gun walking in Fast and Furious.
Republicans now want to see what Justice Department officials said to each other after the letter as the Congressional investigation unfolded and as it became clear that its initial denial was wrong, and whether they retaliated against A.T.F. agents who informed Congress about the problems with the case.
But Mr. Cole, in his letter, said the department had already “substantially complied” with the subpoena.
“The documents responsive to the remaining subpoena items pertain to sensitive law enforcement activities, including ongoing criminal investigations and prosecutions, or were generated by department officials in the course of responding to Congressional investigations or media inquiries about this matter that are generally not appropriate for disclosure,” he said.