The Internal Revenue Service on Tuesday began closing field offices in Northern California, Seattle, Puerto Rico and the New York City area to contain the spread of the novel coronavirus — and all of its tax counseling sites for the elderly. The Social Security Administration closed 1,400 field and hearing offices Monday night.

Federal courts are rescheduling trials. The Food and Drug Administration has suspended inspections of imported food and medical devices, and the Washington Monument has closed to the public.

These public services are the first signs that the public health crisis is forcing the federal government to slow down, even as the Trump administration urges agencies to send their staffs home to work remotely and keep the government running.

The federal government, the nation’s largest employer, was until this week a holdout in confronting the shifts in daily life that health authorities have been urging Americans to make for weeks. But several agencies now are starting to limit their employees’ contact with the public where they can.

Taxpayers and the elderly now have to speak with IRS or Social Security agents by phone to ensure that they do not come into physical contact with one another or with the employees serving them. Families hoping to entertain their out-of-school children in national parks will find about a dozen sites closed from California to Washington, D.C.

The White House Office of Management and Budget, which is holding daily conference calls with federal agency leaders, is urging telework for employees across the country and paid leave for those whose jobs do not allow them to work remotely.

As of Tuesday, though, efforts to clear federal buildings were uneven, underscoring the challenge of such a dramatic, sustained shifting of work patterns in a bureaucracy of 2.1 million employees.

Senior agency leaders were told by top budget office officials this week to prepare to put emergency plans in place that designate which part of their mission is critical to continue during a pandemic and which operations they can drop to keep their employees and the public safe.

So far, there has been no directive to invoke these “continuity of operations” plans. But scattered agencies are taking action.

Social Security closed its 1,250 field offices and 165 sites where administrative law judges hear appeals of rulings on disability applications, after weeks of pressure from employees and the unions that represent them. In theory, business will carry on by phone, officials said.

In reality, the sudden transformation did not unfold seamlessly.

Some employees arrived at work first thing Tuesday morning because they were not yet set up to telework. They watched as customers pulled into parking lots, looking for help with disability claims or with replacing lost Social Security cards. Then they watched them peer into the darkened offices and walk away in frustration.

“We’ve been asking for this for a while. They did it overnight — and failed to get the word out,” said Ralph Dejuliis, a field worker in Oklahoma and national president for the union that represents the federal employees.

Dejuliis said Social Security employees don’t know how they are going to handle a variety of tasks. What if they are not sure people on the phone are who they claim to be? In the past, they made them come to the office to be sure.

Also, only a fraction of the staff have work computers equipped with Softphone, a software program that allows employees to make and receive calls using the Internet.

So they are being asked to use their personal cellphones to talk to dozens of strangers each day. Managers are advising them to block their personal number by using *67 before dialing.

Workers said they are receiving confusing directions from managers about telework.

Milana Bubrinkova, who processes claims in a Chicago district office, said she learned Friday afternoon that her children’s schools were closing.

She asked her manager for permission to telework and didn’t receive a clear decision, she said. She grabbed her work laptop before she left that night. The agency policy allowed for telework under such circumstances, and she wanted to be ready for work Monday morning.

That morning, she said her manager approved her to telework but reprimanded her for taking her computer home without his permission. “I’m trying to find a way to get my work done, and I’m getting reprimanded for it? You cannot make this stuff up.”

Social Security officials did not respond to questions about the incident.

The IRS, weeks from the April 15 tax filing deadline, followed guidance from local public health authorities in some of the country’s hardest-hit communities when it decided to close taxpayer assistance offices on both coasts, officials said. Managers expect that additional taxpayer service offices will close in the coming days and weeks.

The filing deadline has not been changed, but taxpayers who owe the government money will have an additional 90 days to pay.

Also Tuesday, the agency restricted which face-to-face services the rest of the roughly 325 still-open taxpayer assistance offices will provide.

For example, the staff will process only cash tax payments, applications by noncitizens for taxpayer identification numbers and refunds pending confirmation of a taxpayer’s identity.

Chad Hooper, the national president of an association of IRS managers called the Professional Managers Association, said the agency must ensure the safety of thousands of employees who remain at work serving taxpayers, since their jobs cannot be done remotely.

“We should be pulling out all the stops for them,” Hooper said. A particular challenge is making sure employees’ desks and cubicles are cleaned regularly, he said, since many federal agencies are confronting shortages of cleaning supplies and employees are discouraged from bringing their own supplies to work.

The IRS closings follow Monday’s decision by the National Park Service to close the Statue of Liberty National Monument and Ellis Island, both in New York, and the Washington Monument, in the nation’s capital, to the public, following closures of almost a dozen sites last weekend. They include the Alcatraz Island, Muir Woods National Monument and the Golden Gate Recreation Area, all in California, and the Mall and Ford’s Theatre National Historic Site in Washington, D.C.

The pandemic also has upended criminal proceedings in federal courts as officials try to balance the delivery of justice and the preservation of public health. The coronavirus threat has prompted strict protocols all over the country, from the top court in the land to municipal courts in remote areas.

The U.S. Supreme Court has postponed oral arguments for the remainder of March and left unclear when the cases that had been scheduled would be heard. The high court was set to hear arguments March 31 on whether President Trump’s financial records and tax returns should be turned over to Congress and the Manhattan district attorney.

At state and federal courts in New York, what began as recommendations to the public and employees in the justice system have hardened into orders. A statewide memo released Sunday instructed that all “nonessential” matters were to be adjourned at the close of business on Monday.

The virus also prompted the Food and Drug Administration last week to suspend through April most inspections of foreign manufacturers of pharmaceutical products, medical devices and food imported into the United States.

The postponements involve routine surveillance inspections of facilities that make FDA-regulated products. The agency already had suspended most inspections in China.

The FDA has said it will rely more heavily on other tools, such as denying entry of unsafe products into the United States, using information supplied by foreign governments and requesting company records.