South Korean soccer supporters turned an otherwise adrenaline-charged match with Japan into a political flashpoint when they hoisting patriotic banners that hit a sensitive spot.

Dozens of South Korean fans who came to watch the game in Seoul’s Jamsil Olympic Stadium held up a long white banner from the stands which carried a slogan that read, “There is no future for a race oblivious to history.”

Two large tarps with black-and-white images of anti-Japan national heroes, Korean independence activist An Jung-geun and Admiral Yi Sun-shin, were also propped by the crowd, reports The Asahi Shimbun.

Japan cried foul over the “extremely regrettable” slogan and said the government “will respond appropriately based on FIFA rules when the facts are revealed,” Chief Cabinet Secretary Yoshihide Suga said.

Japan Football Association chief Kuniya Daini urged the East Asian federation to “thoroughly investigate” the matter, citing the International Federation of Association Football’s ban on displaying political statements during international games, Kyodo reports.

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