The Pentagon warned 800,000 civilian employees worldwide Wednesday that they will be forced to take unpaid leave if deep budget cuts take effect next week, fueling growing anxiety about the impact of the automatic spending reductions on the nation’s economy and security.

In the most detailed account of the ramifications of across-the-board cuts, called the sequester, Defense Department officials said civilian personnel could be put on leave one day a week for 22 weeks — effectively cutting their pay by 20 percent for nearly six months. According to the Office of Personnel Management, 107,000 of these workers live in the District, Maryland and Virginia.

The nation’s two senior national security officials, Defense Secretary Leon E. Panetta and Secretary of State John F. Kerry, said Wednesday that the reductions would hurt the nation’s global standing.

“There is no mistaking that the rigid nature of the cuts forced upon this department, and their scale, will result in a serious erosion of readiness across the force,” Panetta told employees in a memo.

The Pentagon announcement sparked fresh partisan sniping, with Republicans insisting that it is President Obama’s responsibility to prevent the defense cuts from taking effect.

You’ve heard the word “sequester” mentioned by politicians a lot lately. The Washington Post’s Ed O’Keefe explains what the term means, and why it matters. (The Washington Post)

“As the commander-in-chief, President Obama is ultimately responsible for our military readiness, so it’s fair to ask: what is he doing to stop his sequester that would ‘hollow out’ our Armed Forces?” House Speaker John A. Boehner (Ohio) said in a statement.

Obama, on the other hand, continued his efforts to pressure GOP lawmakers to embrace his proposed fix for the sequester, sitting for eight interviews with handpicked television stations in states that would be hit hard by reductions.

“There’s a better way to do it than this,” Obama told Boston’s WCVB, an ABC affiliate. “But the key is for [Republicans] to go ahead to put forward a balanced, responsible approach that will avoid cuts to things like Head Start programs, medical programs, help for the mentally ill, all these things that have an impact on people’s day-to-day lives.”

The interviews were part of an intensifying push by the president to persuade lawmakers to pass a short-term measure delaying the start of the sequester, which cuts $85 billion in federal spending this year and $1.2 trillion over the next decade.

A report this week by economists at Wells Fargo Securities said Maryland, Virginia and the District — in addition to Hawaii and Alaska — are the places that are likely to be most hurt by the sequester. Federal spending represents about 20 percent of economic activity in those three local jurisdictions — higher than anywhere else in the country, the economists said.

Defense Comptroller Robert F. Hale told reporters Wednesday that $1.1 billion out of $4.8 billion in civilian payroll cuts in fiscal 2013 will come from the paychecks of residents of the District, Maryland and Virginia.

The cuts also will have a “very substantial” impact on the private sector because of reductions in contract spending, Hale said, although he did not provide details. Uniformed personnel are exempt from the sequester.

Obama has backed a Democratic proposal to delay the scheduled reductions through the end of the year by adopting alternative spending cuts — largely by reducing expenditures on farm subsidies — and by limiting tax breaks that benefit the wealthy.

For the longer term, he favors raising new tax revenue from the wealthy and select industries and trimming spending on programs such as Medicare to generate savings. The steps would build on $2.5 trillion in deficit reduction already achieved through earlier deals.

Republicans say raising new tax revenue is out of the question and want to replace the defense part of the sequester with deeper cuts to other domestic programs, including Medicare and Medicaid. Republicans also say the federal budget must be balanced within 10 years, which would require far greater cost-cutting than the sequester.

The Pentagon memo was the latest in a long line of warnings about potential furloughs, which would not start until April because of a required notice period. Many details of who would be furloughed, on what days and for how long would be subject to bargaining with public employee unions.

The 20 percent pay cut would hit civilian defense employees hard, union officials said.

“Taking away one day’s pay every week could mean the difference between covering the mortgage and putting food on the table,” said J. David Cox, president of the American Federation of Government Employees, which represents 270,000 civilian defense workers.

“It really scares the hell out of me,” said a Pentagon official who has worked for the government for more than 12 years.

The official, who spoke on the condition of anonymity because he was not authorized to discuss the matter, said he is particularly worried about making ends meet this year. “It’s going to affect my retirement and now I have a new baby, so my expenses are going to go up with day care and formula and diapers and everything else.”

Dave Miller, a Pentagon intelligence analyst, said that “cutting salaries is like cutting people. It’s the lifeblood of the department.”

“Our younger folks are really going to be hurt by this significantly,” he said. “They just want to do their jobs.”

Pentagon chiefs have been warning in recent days that the reductions are likely to significantly weaken the readiness of a force reeling from the wear and tear of two long wars. If the budget is cut according to the congressional guidelines, by the end of the year, Hale said, two thirds of the Army’s brigade combat teams will be unfit for deployment.

“It could affect their ability to deploy to new contingencies that come up, or even, if it goes on long enough, to Afghanistan.”

Panetta held out hope in the memo that the cuts might be avoided. Even if a deal between the White House and Republicans doesn’t materialize by March 1, when the automatic cuts will take effect, the parties could reach an agreement that spares the Pentagon.

Steve Vogel, Lisa Rein and David Nakamura contributed to this report.