With federal health guidelines growing more stringent by the day, congressional leaders are beginning to reshape the way lawmakers do their jobs to try to slow the spread of the coronavirus.

In a conference call Monday, House Democratic leaders told rank-and-file lawmakers that the schedule would become flexible and that they would not be called back to the Capitol until the next round of economic stimulus legislation is ready for a vote. Aides said the leadership is trying to figure out how to have as few people as possible in the chamber voting at the same time, following President Trump’s announcement that for at least two weeks the public should avoid gatherings of more than 10 people.

After Monday’s vote on an intelligence surveillance law, Senate leaders made plans to replace their weekly Tuesday luncheons, with more than 50 senators and staffers in two cramped rooms just steps from the chamber floor. Majority Leader Mitch McConnell (R-Ky.) was searching for an alternative room; Minority Leader Charles E. Schumer (D-N.Y.) planned for Democrats to hold a conference call instead.

While the novel coronavirus has shuttered schools, churches and restaurants and upended daily life for most Americans, lawmakers have tried to conduct legislative business — specifically to pass billions of dollars in economic relief for a panicked nation. The House broke for a recess after passing its version of the bill early Saturday morning; the Senate returned to work Monday to vote for an extension of the intelligence authority law and work on the stimulus package.

That move drew criticism from some Democrats, who said Senate business was putting lawmakers, staff members and their families at risk, a situation that could have been avoided by passing the bill by voice vote.

“This is a matter of national emergency in a public health crisis in this country, and what kind of example are we setting by coming back to this chamber at risk to our staff and the people and ourselves and our families?” asked Sen. Richard J. Durbin (D-Ill.), the minority whip. “We have members of the Senate going in and out of quarantine, self-quarantine, themselves, and we’re acting like it’s business as usual.”

The Centers for Disease Control and Prevention recommended Sunday that gatherings of more than 50 people should cease. Trump and his coronavirus task force announced Monday that the limit is 10 people and urged older Americans to stay home.

Forty-six members of the Senate are 65 or older; Durbin is 75, and McConnell is 78.

Sen. John Cornyn (R-Tex.), who is 68, tweeted Monday: “My flight to DC has 35 passengers on a plane that holds 170+.”

A major public-sector union Monday called on all federal buildings with more than 50 workers to close — that limit, by definition, would place any roll-call vote of the 100-person Senate in violation, let alone the House with its current 430 members.

“The half-measures taken so far are not enough because too many government workers are still working in full or nearly full offices. Closing buildings halts the large gatherings, just as CDC recommends, allows telework to continue and provides weather and safety leave — as opposed to personal leave — for those who have jobs that are not eligible for telework,” Tony Reardon, president of the National Treasury Employees Union, said Monday.

Yet McConnell gave no indication that the Senate was about to close down.

“The Senate is committed to meeting these uncertain times with bold and bipartisan solutions,” McConnell said Monday in remarks on the Senate floor.

As the angst grew, the Senate agreed to cancel a 5:30 p.m. vote on a procedural motion on the intelligence law, instead passing a temporary extension of some expiring provisions and agreeing to reconsider the law at a later time.

Sen. Christopher A. Coons (D-Del.), who is a daily commuter back and forth to Wilmington, said that his Amtrak train was “awfully empty” and that he would rent a room from a colleague to stay in Washington as the debate unfolds over economic stimulus plans.

“I’m staying until we’re done,” he said.

In a note to her Democratic colleagues Sunday, House Speaker Nancy Pelosi (Calif.) addressed early discussions on the next round of economic stimulus and advised lawmakers to get their staffs to work remotely.

“I am writing to encourage you to take steps to promote social distancing within your Washington, D.C. office as we engage in the District Work Period. This may entail more than half of your Washington staff teleworking from home,” Pelosi wrote.

The Senate was scheduled to be on break this week, but McConnell decided that rather than staying in session all weekend, senators would instead come in this week to handle the intelligence bill and the stimulus package.

Those issues could be handled quickly, but some conservatives are objecting to a speedy debate, possibly prolonging the session. Sen. Tom Cotton (R-Ark.) said Monday that he opposes the bill endorsed by Trump, tweeting that it “doesn’t go far enough & fast enough.”

Senior congressional aides pointed to guidance from the Office of Attending Physician, the top health official in the Capitol, and the Senate Sergeant at Arms, which outlined all the steps taken to mitigate the congressional buildings as possible transmission sites for the deadly virus.

In a memo to all Senate staffers Friday, those offices outlined how the cleaning of offices and “high touch areas” such as elevator buttons had dramatically increased. Crews are using “disinfectant products that meet Environmental Protection Agency (EPA) standards to kill” the virus, according to that memo.

Still, some lawmakers are taking matters into their own hands.

On Monday, Sen. Pat Roberts (R-Kan.) announced that all of his offices in Washington and Kansas would shutter, following the CDC guidelines as he stayed in the Capitol to deal with legislation.

“I have asked my staff to follow all procedures to ensure everyone’s safety, but our plans will still allow us to respond to constituent casework needs and legislative questions. We will do everything we can to help flatten the curve,” said Roberts, 83. “I am remaining in Washington to vote on legislation that is important to the country, and I will be here to do my job which is my obligation to Kansans.”

Seung Min Kim contributed to this report.