The day after, still no one knew what the Italian defender might have said to the French star.

"The Italians did everything they could do to provoke Zidane," France defender William Gallas said.

The Paris-based anti-racism advocacy group SOS-Racism issued a statement Monday quoting "several very well informed sources from the world of football" as saying Materazzi called Zidane a "dirty terrorist."

It demanded that FIFA, soccer's world governing body, investigate and take any appropriate action.

FIFA, which reviews all red cards at the World Cup, would not comment on the specifics.

"This is a disciplinary matter now. I can't give any statements now," FIFA spokesman Markus Siegler said.

Zidane's agent, Alain Migliaccio, was quoted by the BBC as saying the France captain told him the Italian "said something very serious to him, but he wouldn't tell me what."

Whatever it was, it was enough to infuriate Zidane.

"Zizou is someone who reacts to things," said Aime Jacquet, Zidane's coach at the 1998 World Cup. "Unfortunately he could not control himself. It's terrible to see him leave this way."

Zidane's red card was anything but unusual. He was sent off 14 times in his career at the club and international level.

At the 1998 World Cup, he stomped on a Saudi Arabian opponent. Sitting out a two-match ban, he came back to score two goals against Brazil in the final.

Five years ago with Juventus, he head-butted an opponent in a Champions League match against Hamburger SV after being tackled from behind.

The reaction to Sunday's outburst was mixed in France. President Jacques Chirac called Zidane "a genius of world football," and former Sports Minister Marie-George Buffet said Zidane's aggressive act was unforgivable for its effect on children watching the game.

The Independent cited lip-readers for Brazil's Globo TV as concluding that Materazzi had told Zidane that his sister was a "prostitute."

Zidane's teammates had all wanted to help him to one last trophy. Failing that, they refused to kick him when he was down.

"For all that Zidane has done for the national team, you have to say "Thank you and well done,'" said striker David Trezeguet, the only player to miss his penalty kick in the shootout.

French television reported that Zidane would talk about the incident "in the coming days."