WASHINGTON — The Biden administration will begin making 400 million N95 masks available for free to Americans starting next week, now that federal officials are emphasizing their better protection against the omicron variant of COVID-19 over cloth face coverings.

The White House announced Wednesday that the masks will come from the government’s Strategic National Stockpile, which has more than 750 million of the highly protective masks on hand. The masks will be available for pickup at pharmacies and community health centers across the country. They will begin shipping this week for distribution starting late next week, the White House said.

This will be the largest distribution of free masks by the federal government to the public since the COVID-19 pandemic began. In early 2020, then-President Donald Trump’s administration considered and then shelved plans to send masks to all American at their homes. President Joe Biden embraced the initiative after facing mounting criticism this month over the inaccessibility — both in supply and cost — of N95 masks as the highly transmissible omicron variant swept across the country.

After facing similar criticism over a winter shortage of COVID-19 at-home test kits, Biden this week launched a website for Americans to order four rapid tests to be shipped to their homes for free, with the first tests to ship later this month.

The White House said the masks will be made available at pharmacies and community health centers that have partnered with the federal government’s COVID-19 vaccination campaign.

The Centers for Disease Control and Prevention on Friday updated its guidance on face coverings to more clearly state that properly fitted N95 and KN95 masks offer the most protection against COVID-19. Still, it didn’t formally recommend N95s over cloth masks.

The best mask “is the one that you will wear and the one you can keep on all day long, that you can tolerate in public indoor settings,” CDC Director Dr. Rochelle Walensky said last week.

Details were not immediately available on the specifics of the program, including the sort of masks to be provided, whether kid-size ones will be available and whether the masks could be reworn.

The White House said that “to ensure broad access for all Americans, there will be three masks available per person.”

N95 or KN95 masks are more widely available now than at any other time during the pandemic, though they are often more costly than less-protective surgical masks or cloth masks.