The Biden administration, under acute pressure from House lawmakers, moved on Wednesday to ban funding for a prominent virus-hunting nonprofit group whose work with Chinese scientists had put it at the heart of theories that Covid leaked from a lab.

The decision, announced in a letter from the Department of Health and Human Services, came on the heels of a scorching congressional hearing this month at which lawmakers barraged the group’s president with suggestions that he had misrepresented work with virologists in Wuhan, China, where the pandemic began. Republicans went further, demanding that Peter Daszak, the president of the nonprofit, EcoHealth Alliance, be criminally investigated.

For EcoHealth, which relied on federal funding to study the threat of wild animal viruses, the loss of funding is another twist in a saga that has long dominated discussions of how the pandemic began.

In April 2020, under orders from the Trump administration, the National Institutes of Health terminated a grant to EcoHealth amid President Donald J. Trump’s feud with China over the origin of the coronavirus. Three years later, an internal federal watchdog agency determined that the N.I.H. had failed to give a proper cause for ending the grant, which supplied an average of roughly $625,000 per year. The N.I.H. restarted a pared-back version of the award.

Now, with Republicans stepping up their campaign against EcoHealth, and Democrats joining in the anger, the Biden administration has cut off funding for EcoHealth again.

Health officials said they were suspending three active N.I.H. grants to EcoHealth that totaled $2.6 million for last year. And they proposed barring the group from receiving future federal research funding. Such bans, they said, usually last no more than three years, but could be longer or shorter.

In explaining the decision, health officials cited a series of lapses that the N.I.H. had first reported nearly three years ago. Chief among them was EcoHealth’s failure to promptly report findings from studies on how well bat coronaviruses grow in mice, health officials said.

“I have determined that the immediate suspension of EHA is necessary to protect the public interest,” wrote Henrietta K. Brisbon, a health department official, referring to EcoHealth Alliance.

She cited problems in EcoHealth’s monitoring of work done at the Wuhan Institute of Virology, where some of EcoHealth’s grant money was apportioned; the late submission of a progress report; and the possibility that a risky experiment had violated the terms of a grant.

EcoHealth said that it would contest the proposal to bar it from federal funding.

“We disagree strongly with the decision and will present evidence to refute each of these allegations and to show that N.I.H.’s continued support of EcoHealth Alliance is in the public interest,” the nonprofit said in a statement.

EcoHealth has also faced suspicion over a federal grant proposal that it made in 2018 to team up with the same Wuhan virology lab on coronavirus experiments that Republicans believe could have led to the pandemic, despite that project’s never receiving funding.

But for all the scrutiny of EcoHealth, there remains no evidence linking it directly with the beginning of the pandemic.

Federal health officials have said repeatedly that the viruses being studied with taxpayer funding at the Wuhan lab bore no resemblance to the one that set off the coronavirus outbreak, making it impossible that they had been responsible for the public health crisis.

Many scientists, including some whose criticisms of EcoHealth have been cited by House lawmakers in recent weeks, say that early cases and viral genomes point to a different origin for the pandemic: an illegal wild-animal market in Wuhan. Samples collected from the market were revealed last year to contain genetic material from the coronavirus and from animals like raccoon dogs, a scenario that scientists have said is consistent with a market origin.

Representative Brad Wenstrup of Ohio, a Republican who serves as the chairman of the Select Subcommittee on the Coronavirus Pandemic, which held the hearing this month, celebrated the suspension of EcoHealth’s funding. He called it “not only a victory for the U.S. taxpayer, but also for American national security and the safety of citizens worldwide.”

Representative Raul Ruiz of California, the subcommittee’s top Democrat, also welcomed the decision, describing EcoHealth’s conduct as “a departure from the longstanding legacy of good faith partnerships between the N.I.H. and federal grantees.”

Last year, the Biden administration barred the Wuhan Institute of Virology from receiving federal funding for a period of 10 years.

The health department said in a statement that EcoHealth had not complied with federal regulations, necessitating that it, too, now be barred. But the health department did not respond to questions about the timing of that decision, nearly three years after most of the facts cited in its assessment were released by health officials.