WASHINGTON — The Trump administration is formalizing new guidance to recommend that many Americans wear face coverings in an effort to slow the spread of the new coronavirus, as the president is aggressively defending his response to the public health crisis.

The recommendations, still being finalized Thursday, were expected to apply to those who live in areas hard-hit by community transmission of the virus that causes COVID-19. A person familiar with the White House coronavirus task force’s discussion said officials would suggest that non-medical masks, T-shirts or bandannas be used to cover the nose and mouth when outside the home — for instance, at the grocery store or pharmacy. Medical-grade masks, particularly short-in-supply N95 masks, would be reserved for those dealing directly with the sick.

The person spoke on condition of anonymity to discuss the proposed guidance before its public release.

President Donald Trump, who was tested again for coronavirus Thursday using a new rapid test, indicated he would support such a recommendation. “If people wanted to wear them, they can,” he said.

“It’s not a bad idea, at least for a period of time,” Trump had said earlier in the week.

The White House said Trump’s latest test returned a negative result in 15 minutes, and said Trump was “healthy and without symptoms.”

Dr. Deborah Birx, the task force’s coordinator, told reporters the White House was concerned that the mask guidance would lead to a “false sense of security” for Americans. She said new data show that the administration’s social-distancing guidelines were not being followed to the extent necessary to keep virus-related deaths to a minimum.

The discussions on face masks came as the White House moved aggressively to defend its handling of the coronavirus pandemic, particularly its efforts to speed the distribution of ventilators and protective equipment needed by medical professionals.

Trump sent a politically tinged letter to Senate Democratic leader Chuck Schumer of New York objecting to his criticism of the administration’s response. “The Federal Government is merely a back-up for state governments,” Trump wrote. “Unfortunately, your state needed far more of a back-up than most others.”

Trump said states should have done more to stockpile medical supplies before the pandemic.

Vice President Mike Pence also announced Thursday that the White House was considering direct payments to hospitals to cover COVID-19 treatment costs for uninsured Americans.

The emerging guidance on masks appeared to be more limited than a Centers for Disease Control and Prevention draft of the guidance, which suggested the recommendation apply to nearly all Americans, all over the country, according to a federal official who has seen the draft but was not authorized to discuss it.

Officials were expected to limit its geographic scope to just those areas where the virus was spreading rapidly, the official said. The formal announcement is expected as soon as today.

Under the previous guidance, only the sick or those at high risk of complications from the respiratory illness were advised to wear masks.