Brazil's far-right President Jair Bolsonaro has replaced six cabinet ministers in the biggest reshuffle since he came to power two years ago.
Both the foreign and defence ministers have been replaced.
Mr Bolsonaro has seen his popularity plummet in recent weeks over his handling of the coronavirus pandemic.
Brazil's health service is reported to be on the brink of collapse as the country battles a deadly second wave of the virus.
More than 300,000 people have died of Covid-19 in Brazil since the pandemic started, with more than 12 million confirmed cases.
Mr Bolsonaro has consistently opposed quarantine measures, arguing that the collateral damage to the economy would be worse than the effects of the virus itself. He has told Brazilians to "stop whining" about the pandemic.
The president's loyal Foreign Minister, Ernesto Araújo, stepped down from the role after he was heavily criticised by lawmakers over the weekend for damaging Brazil's international standing. They said his poor handling of relations with China, India and the US meant Brazil had insufficient quantities of Covid-19 vaccine.
Mr Araújo has been replaced by Carlos Alberto Franco França. A more surprising change was Fernando Azevedo e Silva replaced as defence minister by Walter Souza Braga Netto.
General Luiz Eduardo Ramos has been named the president's new chief of staff and police commander Anderson Torres has been made justice minister.
The new team is linked to a coalition of right-wing parties that support Mr Bolsonaro in Congress, the BBC's Leonardo Rocha reports.
The bloc is seen as increasingly powerful and even crucial for the political survival of Mr Bolsonaro, who faces the prospect of an impeachment trial over his handling of the pandemic, our correspondent notes.
media captionOne epidemiologist in Brazil fears the country is "becoming a threat to global public health".
Some good news came from the newly-installed Health Minister, Marcelo Queiroga, who said he was pushing to get an earlier delivery of Pfizer-BioNTech vaccine supplies from the US.
Mr Queiroga is the fourth person to serve as health minister in the past year.
Brazil has been struggling with the rollout of its vaccination programme across the vast country. So far, it has been using the Oxford-AstraZeneca vaccine and China's CoronaVac, both of which require two jabs.
Brazil has also placed orders for the Johnson & Johnson and Sputnik V vaccines.
The latest surge in cases has been attributed to the spread of highly contagious variants of the virus.