Coach Georgy Yartsev threw out Mostovoi after he blamed the team's 1-0 defeat by Spain on Saturday on a strenuous training schedule and said Russia was unlikely to qualify from the group stage of the competition.
"Mostovoi has been expelled because of comments he made in the Spanish press," a football federation official said.
Valery Draganov, vice-president
"I really regret this decision, it does not help the team," Draganov told Ekho Moskvy radio.
"Even if Mostovoi spoke out critically against the coach, I don't think it is a reason for such a quick dismissal. We don't have enough players of Mostovoi's calibre -- people like that are worth their weight in gold."
Russia face hosts Portugal on Wednesday in their second Group A match.
