Uruguay star Luis Suarez could be facing a lengthy ban after he was charged by Fifa for allegedly biting Italy defender Giorgio Chiellini at the World Cup.
FIFA said that its disciplinary committee has opened proceedings against Suarez.
If the Liverpool striker - already banned twice before for biting - is found guilty of assaulting an opponent, FIFA rules call for a ban of at least two matches up to a maximum of 24 months.
FIFA asked the team to present evidence by Thursday morning (NZT) and a decision must be published before Sunday, when Uruguay play Colombia in a round-of-16 match.
Uruguay captain Diego Godin headed home an 81st-minute goal to secure a 1-0 in a gritty Group D battle in Natal that ensured his team progressed, while Italy was eliminated in the first round for the second straight World Cup.
But the match was overshadowed by the Suarez incident just moments before Godin's winner. Television replays showed Suarez appearing to attempt to sink his teeth into Chiellini's shoulder in an off-the-ball incident.
Match referee Marco Rodriguez of Mexico appeared not to see the incident and took no action. Chiellini angrily remonstrated with Rodriguez, pulling his shirt off his shoulder to show red marks.
Afterwards a disgusted Chiellini told Italian television: ''He bit me, it's clear, I still have the mark.
''The referee should have blown his whistle and given him a red card,'' he added.
Suarez sought to play down the incident to Uruguayan television, claiming Chiellini had barged him.
''There are things that happen on the pitch and you should not make such a big deal out of them,'' Suarez said.
Uruguay's veteran manager Oscar Tabarez pleaded ignorance of the incident.
''I didn't see it. I'd like to see the images first,'' he told the post-match press conference.
Tabarez also suggested Suarez was being victimised by journalists.
''He is the preferred target for a lot of media,'' Tabarez said. Pressed on the issue, a visibly irritated Tabarez refused to condemn Suarez.
''This is a football World Cup, it's not about cheap morality.''
But despite Suarez's comments, video evidence of the incident appears damning.
If found guilty by FIFA disciplinary chiefs, the incident would almost certainly mean the end of the tournament for Suarez, who was lambasted during the 2010 World Cup for his deliberate goal-line handball that denied Ghana a famous quarter-final victory.
In November 2010, he was banned for seven matches by the Dutch FA after biting PSV Eindhoven's Otman Bakkal on the shoulder when he played for Ajax.
Suarez was dubbed ''the Cannibal of Ajax'' by Dutch media.
In April 2013, he was given a 10-match ban by the English FA after biting Chelsea defender Branislav Ivanovic at Anfield.
He was also banned for eight matches in 2011 for racially abusing Manchester United's Patrice Evra.
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