Brazil's health regulator has reported the discovery of three "preliminary" cases of the Omicron coronavirus variant, two in travellers arriving from South Africa, where it was first detected, and another from Ethiopia.
Positive samples from the two Brazilians will now be sent for further laboratory analysis for confirmation, the Anvisa regulator said in a statement on Tuesday.
A third case was identified in a traveller from Ethiopia, the São Paulo government said Wednesday.
If confirmed, they would be the first Omicron cases in Latin America. Brazil is so far the only country in Latin America to report cases of the new variant.
The new Covid-19 variant, which the World Health Organisation says poses a "very high" risk, has prompted many countries to shut their borders.
he first passenger identified to be infected with the strain arrived at the international airport at Guarulhos in São Paulo on November 23, with a negative coronavirus test.
Two days later, the male passenger and his wife returned to the airport for new tests required to take a flight back to South Africa. Both tested positive and had been vaccinated with the Janseen shot previously.
The third case, said authorities in São Paulo, concerned "a passenger from Ethiopia who disembarked at [Guarulhos airport] last Saturday.
The 29-year-old man, a resident of the municipality of Guarulhos in the São Paulo metropolitan region, had been vaccinated with two doses of the Pfizer vaccine, said authorities.
He has been "isolated at his home since Saturday, without symptoms and being monitored by health surveillance," it added.
Brazil closed its air borders to six African countries (South Africa, Botswana, Esuatini, Lesotho, Namibia and Zimbabwe) on Monday.
Brazil has more than 614,000 deaths since the start of the pandemic, the second country with the most deaths in absolute numbers after the United States.
More than 62 percent of a total population of 213 million is fully immunised and a third dose is being given to at-risk groups and to all adults who were vaccinated more than five months ago.