Brazil's Supreme Court said Tuesday it would hold hearings on two requests to block the Copa América, casting new doubt on the troubled South American football championships five days from kickoff.
Chief Justice Luiz Fux said given the "exceptional nature of the case," he had decided to have the full 11-member court take up the matter in an extraordinary virtual session Thursday.
Organisers are battling the odds to pull off the world's oldest running international football tournament this year despite the coronavirus pandemic.
The 10-nation championships are scheduled to kick off Sunday and run through July 10.
Original co-hosts Argentina and Colombia fell through over a Covid-19 surge in the former and violent anti-government protests in the latter.
With the clock ticking down to the opening match, Brazil stepped in last week as emergency hosts, after the South American football confederation, CONMEBOL, pulled the plug on Argentina.
But Brazil has also been battered by Covid-19, and experts warn it is facing a new surge that a major international sports tournament could exacerbate.
The pandemic has claimed nearly 475,000 lives in Brazil, second only to the United States.
The tournament has become a divisive, politically loaded matter in the country.
President Jair Bolsonaro, who has regularly defied expert advice on containing the pandemic, gave his blessing to host the Copa América.
But epidemiologists have voiced alarm, as have some coaches and players from the 10 countries participating.
'Right to live'
The cases the Supreme Court agreed to hear were brought by national metalworkers' union CNTM and by opposition Congressman Julio Delgado and his Brazilian Socialist Party (PSB).
The union argues that hosting the tournament "risks causing an increase in Covid-19 infections and deaths," the court said in a statement announcing it had agreed to hear the cases.
Delgado and the PSB argue that hosting "violates the fundamental rights to life and health," it said.
Several other requests to block the tournament were also filed in various courts, including another to the Supreme Court by the left-wing Workers' Party (PT) of former president Luiz Inácio Lula da Silva, who is shaping up as Bolsonaro's likely opponent in presidential elections next year.
Originally scheduled for 2020, the Copa América was already delayed by 12 months because of the pandemic.
Brazilian officials have said matches will be held without fans, with mandatory Covid-19 testing for teams every 48 hours, restrictions on their movement and chartered flights to carry them to matches in the four host cities.