A grafitti receives a face mask as an attempt to raise awareness to contain the spread of COVID-19 in Sao Paulo, Brazil, on May 21, 2020. (Xinhua/Rahel Patrasso)

Data from Brazil's civil aviation agency shows there has already been a sharp reduction in U.S.-bound flights from the South American country.

WASHINGTON, May 25  -- The White House on Sunday announced travel restrictions on Brazil, the nation with the second-highest number of COVID-19 cases.

"Today, the President has taken decisive action to protect our country by suspending the entry of aliens who have been in Brazil during the 14-day period before seeking admittance to the United States," the White House said in a statement.

The statement said the action would "help ensure foreign nationals who have been in Brazil do not become a source of additional infections in our country," noting that this measure would not apply to the flow of commerce between the two countries.

President Donald Trump had said last week that he was considering limiting travel from Brazil.

The order is effective at 11:59 p.m. Eastern Daylight Time on Thursday (0359 GMT Friday), and it does not apply to legal permanent residents. A spouse, parent or child of a U.S. citizen or legal permanent resident would also be allowed to enter the country, according to the White House.

Brazil's Foreign Ministry called it a technical decision in the context of "important bilateral collaboration" to fight the COVID-19 pandemic, highlighting U.S. donations of 6.5 million U.S. dollars and a new White House promise of 1,000 respirators.

Earlier in the day, National Security Adviser Robert O'Brien said in an interview with CBS News, "I think that we'll have a 212(f) decision today with respect to Brazil, and just like we did with the UK and Europe and China, and we hope that'll be temporary."

"But because of the situation in Brazil, we're going to take every step necessary to protect the American people," he added.