US President Joe Biden on Monday called on local officials to keep or reinstate mask requirements and pause reopenings as the head of the Centers for Disease Control and Prevention (CDC) said she has a sense of "impending doom" because of the rising number of daily coronavirus cases and hospitalizations and the COVID-19 death rate.

"If we let our guard down now," Biden said, "we could see a virus getting worse, not better. Reinstate the mandate if you let it down," he said, calling it a "patriotic duty" that is crucial to the nation's fight against the virus.

Biden spoke a few hours after CDC Director Dr Rochelle Walensky described a "recurring feeling I have of impending doom" as infections once again are on the rise.

She said at a White House briefing that daily infections are up 10 percent from a week ago; hospitalizations are again on the rise; and deaths, a lagging indicator, averaged nearly 1,000 per day last week after four consecutive days below 850.

"We have so much to look forward to, so much promise and potential of where we are and so much reason for hope," Walensky said, her voice trembling. "But right now, I'm scared.

"When we see that uptick in cases, what we have seen before is that things really have a tendency to surge and to surge big. I just worry that we will see the surges that we saw over the summer and the winter again," she said.

Walensky also expressed concern about increasing travel, saying Americans should limit trips to essential occasions.

"I am asking you to just hold on a little longer, to get vaccinated when you can, so that all of those people that we all love will still be here when this pandemic ends," she said.

The pace of vaccinations is also on the rise. The CDC has reported three straight days of more than 3 million vaccine doses administered, including a record of nearly 3.5 million shots reported on Saturday.

Biden said Monday that 90 percent of American adults will be eligible for COVID-19 vaccines by April 19, and vaccination sites would be within 5 miles of an individual's home. His new timeline surpasses his previous May 1 goal for nationwide eligibility by about two weeks. The remaining 10 percent of the population would be eligible by that time, he said.

"More vaccines, more sites, more vaccinators, all designed to speed our critical work," said Biden, who also announced that the federal government would distribute a record 33 million vaccine doses this week.

New York and New Jersey now have the highest rates of coronavirus infection in the country.

Despite vaccinations, the number of new infections in New Jersey has increased by 37 percent in more than a month, to about 23,600 new cases every seven days. In New York, daily cases have averaged about 50,000 people per week since mid-February.

New Jersey has been reporting about 647 new cases for every 100,000 residents over the past 14 days. New York has averaged 548.

The Biden administration also is racing against the spread of coronavirus variants that may fuel another surge in cases. The number of variant cases in Florida has more than doubled over the past two weeks to a total of 2,330, the highest in the country, according to a report released Sunday by the CDC. The vast majority of variant cases in Florida, as well as the US in general, came from the B.1.1.7 strain, first identified in the UK.

The Biden administration is developing a national "vaccine passport" to allow Americans to prove they have been vaccinated against coronavirus as business and entertainment venues try to reopen, The Washington Post reported Monday.

Five officials, who spoke anonymously, told the Post that federal agencies and private companies are pushing efforts to the White House to develop the scheme.

The vaccine passports are expected to be free and will likely take the form of a scannable code displayed on smartphones through applications, private developers told the Post. Americans without smartphones should be able to print out the passport.

New York state on Friday became the first state in the nation to launch an app that allows people to prove that they have been fully vaccinated against coronavirus or have recently tested negative.

The online program, called the Excelsior Pass, will be accepted at dozens of event, arts and entertainment venues statewide and let people go to events with more people than the state's social gathering limit of 10 people indoors and 25 people outdoors, officials announced in a press release.