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”.