An employee of Brazil's National Health Surveillance Agency (ANVISA) argues with Argentina players Nicolas Otamendi (left) and Marcos Acuna after their World Cup qualifier with Brazil was halted on Sunday
Brazil's World Cup qualifying clash against Argentina was sensationally halted shortly after kick-off on Sunday as controversy over Covid-19 protocols erupted.
Amid incredible scenes at Sao Paulo's Neo Quimica Arena, the match between the two giants of South American football was halted when a group of Brazilian public health officials came onto the pitch, triggering a melee involving team staff and players.
Argentina's players trudged off to the locker room as the furore unfolded.
Argentina captain Lionel Messi later re-emerged from the tunnel without his team shirt on as confusion swept around the stadium.
The stunning intervention came just hours after Brazil's health authorities said four players in Argentina's squad based in England should be placed in "immediate quarantine" for breaching Covid-19 protocols.
According to Brazil's National Health Surveillance Agency (ANVISA), Premier League players Giovani Lo Celso (Tottenham), Emiliano Martinez (Aston Villa), Emiliano Buendia (Aston Villa) and Cristian Romero (Tottenham) provided "false information" upon their entry to Brazil.
Romero, Lo Celso and Martinez were all in the Argentina starting line-up that kicked off Sunday's game -- triggering the intervention onto the field of officials wearing ANVISA shirts.
The four Premier League players were accused of failing to disclose that they had spent time in the United Kingdom in the 14 days prior to their arrival.
"We got to this point because everything that ANVISA directed, from the first moment, was not fulfilled," ANVISA director Antonio Barra Torres said on Brazilian television.
"(The four players) were directed to remain isolated while awaiting deportation, but they did not comply. They went to the stadium and they entered the field, in a series of breaches," the official added.
A government order dating from June 23 prohibits the entry into Brazilian territory of any foreign person from the United Kingdom, India or South Africa, to prevent the spread of variants of the coronavirus.
"ANVISA considers that this situation represents a serious health risk and recommends that the local health authorities (of Sao Paulo) order the immediate quarantine of the players, who are prohibited from taking part in any activity and from remaining on Brazilian territory," the agency said in a statement earlier Sunday.
ANVISA said Brazil's Federal Police had been notified so that "the necessary measures are taken immediately".
With the game apparently abandoned, Brazil's squad began a practice game on the arena with Argentina's team having reportedly left the stadium.
South American football's governing body CONMEBOL said in a statement that the game had been "suspended" but did not say whether the match would resume or be replayed.
"By decision of the match referee, the match organized by FIFA between Brazil and Argentina for the qualifiers for the the World Cup is suspended," CONMEBOL said in a statement.
"The referee and the match commissioner will submit a report to the FIFA Disciplinary Committee, which will determine the steps to follow. These procedures adhere strictly to current regulations."
CONMEBOL added that as the qualifiers were part of a FIFA competition, it would be up to football's global governing body to determine the next course of action.
"The World Cup qualifiers is a FIFA competition," CONMEBOL said. "All decisions concerning its organization and development are the exclusive power of that institution.
The controversy comes after nine Brazilians based in the Premier League failed to travel to South America following objections from their clubs.