Kyodo reported two women filed a criminal complaint in Osaka alleging Ito sexually assaulted them in June. His lawyer said the player denies the allegations and has filed his own complaint saying they are false.
The Japanese Football Association said Ito, who plays for French side Stade de Reims, had to leave the squad so they could create an environment where players could concentrate only on football.
"It would have been best if he stayed with us until the end of the tournament. But we had to listen to the Japan FA and he had to leave," Moriyasu told reporters.
"I haven't built a team that will suffer if we lose one player. We have players who can play to the maximum potential so I'm confident it (Ito's departure) will not affect my team.
"I have spoken to Ito, he's fine enough to speak. Mentally I don't think he's in a state to play in a high-intensity football match."
Moriyasu had said after their last-16 win over Bahrain that they were aware of the article published in a Japanese weekly magazine that reported the allegations but refrained from taking action at the time as he wanted to confirm the facts.
