The Biden administration has renewed Trump-era Covid-19 travel bans on non-US visitors from Brazil and most of Europe, including the UK and Ireland.
The White House also imposted a new ban on South Africa over its virus variant.
Former President Donald Trump had ordered the bans to end on 26 January as one of his final acts in office.
The new travel restrictions came as Minnesota recorded the first US case of the Brazil variant from a resident who had recently travelled to that country.
“This case marks the first documented instance of the Brazil P.1 variant in the United States,” said the Minnesota Department of Health on Monday.
The unnamed patient lives in the Minneapolis-Saint Paul area, said the department.
With the national coronavirus case count above 25 million cases, the US is seeking to ramp up its vaccine rollout.
White House Press Secretary Jen Psaki confirmed the decision to continue the restrictions on foreign travellers on Monday.
“On advice of our administration’s medical and Covid team, President Biden has decided to maintain the restrictions previously in place for the European Schengen area, the United Kingdom, Republic of Ireland, and Brazil,” Ms Psaki told reporters.
“With the pandemic worsening and more contagious variants spreading, this isn’t the time to be lifting restrictions on international travel. And in light of the contagious variant, B1351, South Africa has been added to the restricted list.”
All international travellers must also present a negative test within three days of air travel to the US.
Travel restrictions have been in place since mid-March.
When Mr Trump ordered a ban on flights from China in February, citing the “Chinese virus”, Mr Biden railed against “Donald Trump’s record of hysterical xenophobia”. At the time, the Biden campaign denied the remark was about Mr Trump’s travel ban.
When asked about Mr Biden’s stance in light of the “xenophobic” remark, Ms Psaki said: “He was critical of the former president for having a policy that was not more comprehensive than travel restrictions and he conveyed at the time – and more recently – the importance of having a multi-faceted approach.”
On Monday, Mr Biden suggested his initial goal of 100m vaccines administered in the first 100 days of his presidency may rise to 150m. The president added that he believes anyone who wants a vaccine should be able to get one by this spring.
So far, the new administration has also mandated mask-wearing on federal property and interstate travel, and is proposing an economic rescue package worth $1.9tn (£1.4tn).
However, Senate Republican leader Mitch McConnell said on Monday he was against “an imprecise deluge of borrowed money that would direct huge sums toward those who don’t need it”.
Some media have questioned whether the new president’s target of one million shots per day should be bolder. Last week, at the tail-end of the Trump administration, the US reached an average of around 980,000 vaccine doses administered daily.
When an Associated Press news agency reporter asked last Thursday why Mr Biden had not aimed higher, he shot back: “You all said it’s not possible. Come on, give me a break man.”
But CNN rated the president’s claim as false.
During Monday’s press conference, a reporter suggested to Mr Biden that he had changed his tone on defeating the public health crisis, pointing out that as a candidate he had vowed to “shut down” Covid-19, only to say last week: “There’s nothing we can do to change the trajectory of the pandemic in the next several months.”
Mr Biden replied: “What I meant was it took a long time to get here and it’s going to take a long time to beat it.”
“I’m confident we will beat this virus,” he added, “but we’re still going to be talking about it in the summer and dealing with it in the fall.”
The US has had more than double the cases of the next highest country, India. There have been over 420,000 deaths – nearly twice as many as Brazil, the second highest.
New York City – the most populous in the country – has postponed plans for three mass vaccination sites due to a low supply of vaccine doses.
City authorities were co-ordinating plans to turn two baseball stadiums as well as an outlet mall into inoculation hubs, but vaccine supply has not kept up with demand.
At a press conference earlier today, Mayor Bill de Blasio confirmed the change of plans: “We want to get those to be full blown, 24-hour operations, but we don’t have the vaccine.”
He said if supply met demand, roughly 500,000 New Yorkers could be vaccinated each week, but the city will probably add just over 100,000 doses next week to its limited inventory.
Also on Monday, California lifted a stay-at-home order imposed in December as officials said projections for hospital intensive care capacity had improved. The Golden State has been hard hit by a post-holiday surge that stretched hospitals to their limits.
Governor Gavin Newsom is facing intense criticism over his refusal to share the data used by his administration to drive Covid policy decisions. State health officials said the metric is complicated, and would only confuse the public if released.
The stay-at-home order had been in place for Southern California, the San Joaquin Valley and the Bay Area, which are home to over 90% of the state’s residents.
The region is still under restrictions, however, non-essential businesses are still to remain closed and restaurants must serve outdoors only.