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The White House has invoked executive privilege over documents at the center of the stand-off between Attorney General Eric Holder and Rep. Darrell Issa, the Republican chairman of the House Oversight and Government Reform Committee investigating the Justice Department's "Fast and Furious" program.

"The President has asserted executive privilege over the relevant post-February 4, 2011, documents," deputy attorney general James Cole wrote Issa this morning.

"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 move comes ahead of an expected committee vote on whether to put Holder in contempt of Congress for refusing to turn over the documents. It is the first time President Obama has asserted executive privilege in a dispute with Congress.

In a letter Tuesday to President Obama, Holder formally requested presidential intervention, citing "significant, damaging consequences" in releasing the documents and "separation of powers concerns."

The documents "were not generated in the course of the conduct of Fast and Furious. Instead, they were created after the investigative tactics at issue in that operation had terminated and in the course of the Department's deliberative process concerning how to respond to congressional and related media inquiries into that operation," he wrote.

Holder has said the Department has already provided "extraordinary" access to documents and administration officials to answer questions about the incident.

Still, Issa and Republicans on the committee believe the as yet undisclosed information is critical to understanding how the administration responded to the unfolding scandal surrounding program that allegedly allowed U.S. weapons to cross the border into Mexico in order to track gun runners. One of the weapons was later found to be used in the shooting death of a U.S. border patrol agent.

Republican committee members say the documents in question could shed light on whether officials participated in a cover up.

"Our purpose has never been to hold the attorney general in contempt. 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," Rep. Issa said today during a committee hearing.

"More than eight months after a subpoena, and clearly after the question of executive privilege could have and should have been asserted, this untimely assertion by the Justice Department falls short of any reason to delay today's proceedings," he said.

Sen. Chuck Grassley, R-Iowa, who has been leading a Senate investigation into Fast and Furious, said Obama's move raises "monumental questions."

"How can the President assert executive privilege if there was no White House involvement? How can the President exert executive privilege over documents he's supposedly never seen? Is something very big being hidden to go to this extreme?" he said in a statement.

Obama administration officials say the assertion of privilege over non-presidential executive branch communications is not unprecedented.

President Bill Clinton used executive privilege 14 times and President George W. Bush invoked it six times, officials said, including in cases that involved documents similar to those sought in the Fast and Furious congressional inquiry.

This post has been updated.

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