Not even concern over the spread of the coronavirus was enough to spare dozens of people from jury duty Monday at the Stout Center for Criminal Justice.

Until, suddenly, it was.

About an hour after summoning 200 potential jurors to court — several of whom expressed concern over having to show up while many businesses and schools across the region shut down — President Judge Idee Fox dismissed them all. By afternoon, she had announced that Philadelphia’s First Judicial District would suspend all nonessential proceedings, including jury duty and trials, through at least April 1.

The moves came days after some of the region’s suburban counties and federal courts across Eastern Pennsylvania had taken similar steps, prompting some of those summoned to question why, amid government recommendations to avoid crowds of more than 50 people, the city’s courts had not acted sooner.

“It should have been closed down,” said Jim Fletcher of Germantown as he trudged, summons in hand, into the main jury room Monday morning. Asked whether he would take any precautions to protect himself, he shook his head and replied: “Let’s hope they’re doing that for me.”

The union representing the city’s public defenders circulated an open letter Sunday night warning that continuing with trials and nonessential hearings as normal would put not only potential jurors but also attorneys, their clients, and witnesses at risk.

Meanwhile, within the ranks of the District Attorney’s Office, a group of prosecutors began drafting a request to District Attorney Larry Krasner, asking that he refuse to send his staff to court in an effort to force court administrators’ hands.

The announcement of the suspension of most court operations Monday afternoon came before that letter could be sent, sources familiar with the document said. But its sentiments echoed a similar joint-missive sent by three associations that represent immigration judges, lawyers, and prosecutors to the office that runs the nation’s federal immigration courts — one of the few other court systems in the region operating with only minimal adjustment Monday.

By day’s end, Krasner had announced his own set of changes to address the crisis, including decisions to loosen his office’s charging policies for nonviolent crimes and its responses to bail requests.

“I think the pandemic requires that,” he said.

City court administrators had taken some steps Monday morning to mitigate potential spread. The courthouse’s lobby was devoid of its usual morning bustle. Sheriff’s deputies and janitorial staff wearing face masks scrubbed down metal detectors and other surfaces, while in the central jury waiting area, the crowd of roughly 120 potential jurors who showed up were asked to sit with two empty chairs between them.

The elevator bay — usually teeming with attorneys, defendants, and spectators jostling to reach courtrooms on the upper floors — attracted a sparser-than-usual crowd, with security staff limiting five people to each new elevator that arrived.

Though most of the core business in Common Pleas, Municipal, and Family Courts will be suspended for weeks, including in-person probation reporting, some core functions will continue.

One judge will remain on duty daily to handle emergency civil matters, including those related to medical crises and public safety. Meanwhile, arraignments, bail hearings, and emergency requests for protection-from-abuse orders will continue around the clock as normal, court administrators said.

But Krasner raised doubts that he would be able to continue staffing those limited court functions, citing quarantines among his own staff.

In his own announcement Monday, Krasner said his office would no longer seek pretrial detention or cash bail for anyone arrested for a nonviolent felony or misdemeanor offense. Prosecutors will continue to work with public defenders, he said, to review early parole and release petitions, bail reductions, and requests to lift detainers for inmates who do not pose a public safety threat.

Meanwhile, he urged Philadelphia police to reevaluate their arrest practices in light of the crisis and prioritize arresting only those who present a public safety risk.

“We are hopeful that the Philadelphia police will change arrest patterns in order to ensure only truly dangerous offenders are taken into custody and that the prison system is not stressed beyond what it can bear,” Krasner said.

Staff writers Samantha Melamed, Chris Palmer, and Jeff Gammage contributed to this article.