The danger of looming budget cuts could soon become all too real.

If lawmakers and President Obama can’t agree on a plan to avert the $85 billion across-the-board spending cuts set to take effect March 1 -- known as the sequester -- then the federal background check system for vetting gun buyers could face cuts, according to a letter FBI officials sent to lawmakers earlier this month.

In a letter to Senate Appropriations Committee chairwoman Barbara Mikulski (D-Md.), FBI director Robert Mueller warned that the spending cuts would force his agency to furlough more than 2,000 workers, a loss of manpower that would ripple throughout the bureau.

"Delays in processing and adjudicating NICS requests increases the risk of firearms being transferred to a convicted felon or other prohibited person," Mueller wrote in the letter.

In a speech Tuesday, Obama urged Congress to pass his plan, which combines spending cuts and tax increases on the wealthy, to avoid the sequester. Republicans have said they won't raise taxes to cut the deficit.

The warning comes as demand for guns -- and the background checks they require -- surges in the wake of the Newtown shooting. Background checks for gun purchases jumped to a new record in December, according to FBI data. And gun store owners have reported anecdotally that demand has been so high in some cases that they don’t have enough guns and ammunition to meet it.

The gun background check system would be just one of many casualties of the budget cuts if they take effect. Agriculture Secretary Tom Vilsack said his agency would be forced to furlough nearly one-third of its workers, a move that could mean the meat industry shutting down for up to two weeks for lack of inspectors. The sequester could also cost the U.S. economy 750,000 jobs by some estimates and up to 1 million jobs by others.

(Hat tip: USA Today)

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  • Defense

    About half of the sequestration consists of <a href="http://armedservices.house.gov/index.cfm/files/serve?File_id=b276f1fe-4529-4f63-bf10-d26d0444797c" target="_hplink">defense spending cuts</a>, which would "drastically" shrink the military and cancel defense contracts, according to the House Armed Services Committee. (John Cantlie/Getty Images)

  • Emergency Response

    The sequestration would slash funding for the government's <a href="http://www.whitehouse.gov/the-press-office/2013/02/08/fact-sheet-examples-how-sequester-would-impact-middle-class-families-job" target="_hplink">emergency response system</a> for disasters such as hurricanes, according to the White House. (Bruce Bennett/Getty Images)

  • Unemployment Benefits

    <a href="http://www.whitehouse.gov/the-press-office/2013/02/08/fact-sheet-examples-how-sequester-would-impact-middle-class-families-job" target="_hplink">Checks for unemployed people</a> looking for work would shrink by up to 9 percent, according to the White House. (J Pat Carter/AP Photo)

  • Homelessness Programs

    More than 100,000 <a href="http://www.whitehouse.gov/the-press-office/2013/02/08/fact-sheet-examples-how-sequester-would-impact-middle-class-families-job" target="_hplink">formerly homeless people</a> would lose their current housing as a result of sequestration, according to the White House. (Mark Lennihan/AP Photo)

  • Rental Assistance

    About 125,000 low-income families would be at risk of losing their housing because of <a href="http://www.whitehouse.gov/the-press-office/2013/02/08/fact-sheet-examples-how-sequester-would-impact-middle-class-families-job" target="_hplink">rental assistance cuts</a>, according to the White House. (Barry Gutierrez/AP Photo)

  • Mental Health Programs

    The sequestration would eliminate care for up to 373,000 <a href="http://www.whitehouse.gov/the-press-office/2013/02/08/fact-sheet-examples-how-sequester-would-impact-middle-class-families-job" target="_hplink">"seriously mentally ill" people</a>, according to the White House. (Eric Gay/AP Photo)

  • Food Safety

    The FDA would conduct fewer <a href="http://www.whitehouse.gov/the-press-office/2013/02/08/fact-sheet-examples-how-sequester-would-impact-middle-class-families-job" target="_hplink">food inspections</a> as a result of sequestration, according to the White House. (Mike Hentz/AP Photo)

  • Head Start

    About 70,000 children would lose access to the early education program <a href="http://www.whitehouse.gov/the-press-office/2013/02/08/fact-sheet-examples-how-sequester-would-impact-middle-class-families-job" target="_hplink">Head Start</a> as a result of the sequestration, according to the White House. (Elaine Thompson/AP Photo)

  • Small Business Assistance

    The government's <a href="http://www.whitehouse.gov/the-press-office/2013/02/08/fact-sheet-examples-how-sequester-would-impact-middle-class-families-job" target="_hplink">small business loan guarantees</a> would get slashed by nearly $1 billion as a result of the sequestration, according to the White House. (Steven Senne/AP Photo)

  • Scientific Research

    The sequestration would slash <a href="http://www.whitehouse.gov/the-press-office/2013/02/08/fact-sheet-examples-how-sequester-would-impact-middle-class-families-job" target="_hplink">scientific research funding</a> at the National Institutes of Health (NIH) and National Science Foundation (NSF), according to the White House. (Spencer Platt/Getty Images)

  • HIV Prevention

    Up to 424,000 <a href="http://www.whitehouse.gov/the-press-office/2013/02/08/fact-sheet-examples-how-sequester-would-impact-middle-class-families-job" target="_hplink">HIV tests</a> would be on the chopping block as a result of sequestration, according to the White House. Thousands of people with HIV also would lose access to "life-saving" HIV medications. (Darren Abate/AP Images for AIDS Healthcare Foundation)