Brazil's popular justice minister has resigned from President Jair Bolsonaro's government, accusing him of political interference.
Sergio Moro, a former judge who oversaw the country's biggest anti-corruption probe, quit after the president fired the federal police chief.
Mr Moro said Mr Bolsonaro demanded someone who would provide him with direct intelligence.
In a public address, the far-right president called the claims "baseless".
"The appointment is mine, the prerogative is mine and the day I have to submit to any of my subordinates I cease to be president of the republic," Mr Bolsonaro said flanked by most of his cabinet in the presidential palace in Brasília.
But Brazil's public prosecutor Augusto Aras asked the Supreme Court to allow an investigation into Mr Moro's allegations against the president.
How did the political row escalate?
The dismissal of federal police chief Mauricio Valeixo was announced, with no further details, in the official gazette on Friday.
On Thursday, Mr Moro had threatened to resign if Mr Valeixo - his ally - were dismissed, but then said he would stay if he were allowed to choose a replacement.
Earlier this month, the president sacked his Health Minister Luiz Henrique Mandetta for his response to the coronavirus pandemic. The minister had advocated social distancing, which Mr Bolsonaro has scorned.
Fighting corruption was a central issue for Jair Bolsonaro in his 2018 presidential campaign.
But Mr Moro on Friday accused the president of meddling in federal police efforts to fight corruption.
The sound of pot-banging protests rang out in cities across Brazil after his resignation was announced.
Blow to the Bolsonaro government
The departure of Jair Bolsonaro's most popular minister is a blow to his government - Sergio Moro was a star minister. He was seen by his supporters as an anti-corruption crusader.
It is a departure that Jair Bolsonaro has clearly taken personally too, judging by his 45-minute television address on Friday afternoon. He recounted being snubbed by Mr Moro at the airport a few years ago, and accused him of not caring enough after he was stabbed during the campaign in 2018.
There is no doubt Mr Bolsonaro looks weaker now than ever - the events of Friday mark one of the most dramatic days in Brazilian politics in recent years.
Many are wondering who will be next - will the likes of Paulo Guedes, his economy minister and another star member of the cabinet, remain loyal or jump to save his reputation?
All this drama is distracting from a more urgent crisis - the number of coronavirus cases and deaths are rising ever faster each and every day.
Who is Moro?
Seen as an anti-corruption crusader, Mr Moro was a star pick when Mr Bolsonaro asked him to join the government.
Mr Moro earlier oversaw a huge corruption probe known as Operation Car Wash, which exposed billions of dollars in bribes and ended in the jailing of many powerful businessmen and politicians, including leftist former President Luiz Inácio Lula da Silva.
He once said he "would never enter politics", but later agreed to serve in Mr Bolsonaro's cabinet in order to fight corruption and organised crime.
He was promised full autonomy for his department, which united the justice and public security portfolios in a so-called "super ministry".