Japan has lodged a protest with the East Asian Football Federation demanding an investigation into a politically charged banner that was displayed at the East Asian Cup finale against South Korea on Sunday.

During the match in Seoul, which Japan won 2-1 with an injury-time goal, South Korean supporters raised a long horizontal banner referring to Japan’s 1910-45 colonial rule over the Korean Peninsula that read: “There is no future for a race oblivious to history.”

The banner, which stretched across a wide section of the stands and was written in Hangul, was displayed for about an hour from kickoff.

“I was hoping something like this would not occur this time, so it’s unfortunate,” Japan Football Association chief Kuniya Daini said Monday. “We ask the East Asian federation to thoroughly investigate the matter and act in the appropriate fashion.”

Daini said that he asked the organizer during halftime to have the banner taken away.

Chief Cabinet Secretary Yoshihide Suga told reporters the government “will respond appropriately based on FIFA rules when the facts are revealed.”

Meanwhile, during the match, Japanese supporters briefly waved a Japanese rising sun flag, a symbol of Japan’s militaristic past, but put it away after organizers asked them to do so, according to several Japanese fans and South Korean media.

The Korea Football Association told Yonhap News Agency on Monday that the organization has no plans to take action over the issue.

FIFA prohibits political statements of any kind during games. Soccer’s world governing body punished South Korea earlier this year for a similar event at last summer’s London Olympics when Park Jong-woo raised a sign saying, “Dokdo is our territory” after the bronze-medal match. Dokdo refers to a pair of rocky South Korea-controlled islets in the Sea of Japan that Japan claims as Takeshima. The sign was apparently not his.

FIFA, jointly with the International Olympic Committee, banned Park for two games and withheld his bronze medal until February.

It remains to be seen how thorough the EAFF probe will be. The federation is headed by a South Korean, Chung Mong-gyu.

South Korean fans also tried to bring a similar banner into the finale of the East Asian Cup’s women’s competition on Saturday night, but were stopped by the Korea Football Association, South Korea’s soccer authority, according to South Korean media.