The Brazilian president, Jair Bolsonaro, has announced live on television he has tested positive for coronavirus.

“It came back positive,” a mask-wearing Bolsonaro told a hand-picked group of reporters on Tuesday lunchtime outside his official residence.

“There’s no reason for fear. That’s life,” the president added. “Life goes on. I thank God for my life and the role I’ve been given to decide the future of this great nation that is called Brazil.”

Bolsonaro, 65, has repeatedly trivialized the pandemic and flouted social distancing, even as Brazil became the second-worst-hit country after the United States, with more than 65,000 deaths and 1.6m confirmed cases.

In March, as Covid-19 claimed its first victims in Brazil, the far-right populist used an address to the nation to brag that, if infected, he would quickly shake off the illness thanks to his “athlete’s background”.

Since then, Bolsonaro has continued to attend social events and political rallies, often wearing masks incorrectly, or not wearing them at all.

After announcing his positive result on Tuesday, Bolsonaro stepped back from the reporters he was addressing, removed his mask and, grinning, said: “Just look at my face. I’m well, fine, thank God … Thanks to all those who have been praying for me … and to those who criticise me, no problem, carry on criticising as much as you like.”

Bolsonaro’s diagnosis comes just three days after he had lunch at the home of the US ambassador to Brazil, Todd Chapman, in the capital, Brasília.

Also present at that Independence Day celebration were several top cabinet members, including the foreign minister, Ernesto Araújo, defence minister, Fernando Azevedo, and the president’s son, Eduardo, a politician who is Steve Bannon’s representative in South America. The men were photographed without face masks.

Reports of Bolsonaro’s possible infection first emerged on Monday evening, with local news outlets reporting that he had been tested after developing coronavirus symptoms, including a 38C temperature and a persistent cough.

An MRI of Bolsonaro’s lungs was also taken, with the president telling supporters it had shown them to be “clear”.

The newspaper O Globo said it understood Brazil’s president had started complaining of tiredness on Saturday night, after his lunch with the US ambassador, and continued feeling unwell on Sunday.

Bolsonaro has repeatedly downplayed the risks of Covid-19 and urged Brazil to get back to work to avoid a devastating economic crash but he is now the second member of his family suffering its effects.

The 80-year-old grandmother of Brazil’s first lady, Michelle Bolsonaro, was reportedly intubated on Sunday, after being admitted to hospital with coronavirus last Wednesday.

According to the G1 news website, Maria Aparecida Firmo Ferreira, who is reportedly estranged from the presidential clan, was found collapsed in the street by passersby and taken to a hospital in Ceilândia, a satellite city outside Brasília.

Bolsonaro’s response to the coronavirus has sparked a domestic and international outcry, with many directly blaming him for the high death toll. Brazil currently lacks a permanent health minister after two were forced from their jobs in less than a month after clashing with Bolsonaro over the pandemic.

On Monday night Bolsonaro’s son, Carlos, attacked critics of his father who he claimed were willing the president’s death.

“The immense number of people rooting for the death of the head of the executive right now should trigger an immediate show of solidarity from other [political] leaders,” Carlos Bolsonaro tweeted.

Another prominent politician, the mayor of the biggest city in the Amazon, Manaus, was flown to hospital in São Paulo on Monday after also falling ill with coronavirus last week.

“The doctors are optimistic and so are we,” Arthur Virgílio, who had reportedly been receiving non-invasive respiratory support, said in a WhatsApp message to the Guardian.