Real Madrid coach Jose Mourinho could be suspended up to 12 games for his altercation with Barcelona assistant coach Tito Vilanova during a Spanish Supercup game-ending brawl.
The Spanish soccer federation opened disciplinary proceedings against the Spanish clubs on Tuesday, six days after Barcelona won the trophy in a match marred by the finale.
Mourinho walked toward Vilanova and appeared to poke him in the eye during the onfield melee between the benches.
Under rules 98 and 100 of the federation disciplinary code, the Portuguese coach could be banned between four to 12 games while Vilanova - whose actions are being investigated under articles 111 and 122 - could be sanctioned for four games after retaliating with a push.
Mourinho apologized on Tuesday to Madrid fans for his actions.
"(I) wish to apologize to Madridistas, and only to them, for my attitude in our last game," Mourinho said in a statement posted on Madrid's website. "Some people are better adapted to the hypocrisy in football than I am, and they hide their faces and speak in whispers deep inside tunnels.
"I'm not learning to be a hypocrite, and I don't want to."
The altercation came when both benches cleared onto the field following Madrid defender Marcelo's ugly challenge on Cesc Fabregas just before injury time.
Marcelo and teammate Mesut Oezil and Barcelona striker David Villa were all subsequently shown red cards and were all given one-game bans by the federation on Tuesday.
The clubs have 10 days to present their cases.
Barcelona won the match at the Camp Nou 3-2 and the two-leg series 5-4 for its 10th Supercup.