The Asian Football Confederation on Thursday charged Kawasaki Frontale with discrimination after their fans raised a controversial wartime Japanese flag during a midweek Asian Champions League match in South Korea.
According to article 58.3 of the AFC's disciplinary and ethics code, a team would face a minimum penalty of two matches in an empty stadium plus a fine of at least $15,000.
The J. League club was notified of the decision through the Japan Football Association. The AFC will hear Frontale's side of the story before making a final decision on the penalty at a disciplinary committee meeting in time for Kawasaki's next ACL match at home on May 9.
In Kawasaki's 1-0 win at Suwon Bluewings on Tuesday, two Frontale supporters waved the 16-ray rising sun flag, nearly provoking a post-game riot.
In related news, Gamba announced on Thursday the supporters' group responsible for hoisting a banner with a logo resembling a Nazi Schutzstaffel (SS) symbol in their match against Cerezo Osaka has been dissolved.
Members of the group, who notified the team they have disbanded, have also been banned from games indefinitely, Gamba said on their official website. Gamba had already issued a blanket ban on flags and banners at all home and away games.
J. League chairman Mitsuru Murai, who apologized for the April 16 incident last week, said no punishment has been handed down to Gamba yet.
"We have not decided at this point in time how we deal with the situation from here," Murai said following a meeting of the league's board, where Gamba president Takashi Yamauchi held a briefing.
Murai added both the league and club were slow to act.
"I have been told that everyone associated lacked the awareness to deal with the problem," he said.