The White House says it is restricting travel from Brazil to the United States, two days after the South American nation became the world's No.2 hotspot for coronavirus cases.
The travel ban is a blow to right-wing Brazilian President Jair Bolsonaro, who has followed the example of US President Donald Trump in addressing the pandemic, fighting calls for social distancing and touting unproven drugs. The Brazilian president's office did not respond to a request for comment.
"The US maintains a strong partnership with Brazil and we work closely to mitigate the socioeconomic and health impacts of COVID-19 in Brazil," the US embassy in Brasilia said in a statement on Sunday.
The new restrictions come into force on May 28, prohibiting most non-US citizens from travelling to the United States if they have been in Brazil in the past two weeks. Green card holders, close relatives of US citizens and flight crew members, among select others, would be exempt.
Brazil's foreign ministry called it a technical decision in the context of "important bilateral collaboration" to fight the COVID-19 pandemic, highlighting US donations of $US6.5 million and a new White House promise of 1000 respirators.
White House press secretary Kayleigh McEnany said the new restrictions would help ensure foreign nationals did not bring additional infections to the United States but would not apply to the flow of commerce between the countries.
An adviser to Brazil's president played down Trump's move, highlighting shared views on fighting the virus with unproven anti-malarial drugs such as hydroxychloroquine.
"There is nothing specific against Brazil," international affairs adviser Filipe Martins tweeted.
The US Food and Drug Administration warned last month about using the drug to treat COVID-19, citing "reports of serious heart rhythm problems".
Bolsonaro's insistence on the drug's potential and defiance of state isolation orders pushed out two health ministers, both doctors, before the current acting head, an army general, issued guidelines to expand use of the drug in coronavirus cases.
Brazil's confirmed cases rose by 15,813 on Sunday to 363,211, second in the world behind the United States, with more than 1.6 million cases.
Brazil's death toll rose by 653 to 22,666, well behind nearly 100,000 US deaths.