FIFA has opened disciplinary proceedings against Uruguay forward Luis Suarez after Italy defender Giorgio Chiellini accused him of biting during the South Americans' 1-0 Group D victory at the World Cup.
The probe means Suarez, twice previously banned for biting, may be hit with another lengthy suspension despite escaping punishment during the match.
"FIFA can confirm that disciplinary proceedings have been opened against the player Luis Suarez of Uruguay," the world football body said in a statement.
FIFA said Suarez and the Uruguayan FA had until 5 p.m. Brasilia time (2100 UK time) on Wednesday to "provide their position and any documentary evidence they deem relevant".
FIFA is probing what it called an apparent breach of two articles of the organisation's disciplinary code. One covers infringements and the other offensive behaviour and fair play.
Suarez and Chiellini clashed in the Italian penalty area 10 minutes from the end of the match which sealed Uruguay's progression and Italy's elimination from the tournament.
Chiellini furiously pulled open his shirt to show the mark to the referee.
Reuters photographs show what appeared to be bite marks on his shoulder and pictures also showed Suarez sitting on the ground holding his teeth immediately after the incident.
The Italians were still complaining about it when Uruguay's Diego Godin scored with an 81st-minute header to secure the win.
"It was ridiculous not to send Suarez off," Chiellini told Rai TV. "It is clear, clear-cut and then there was the obvious dive afterwards because he knew very well that he did something that he shouldn't have done."
Suarez contested that version of events, however.
"Those are situations that happen on the pitch. We were both just there inside the area. He shoved me with his shoulder, and my eye got left like that also," he said in reference to Chiellini's mark.