Japanese J-League side Gamba Osaka have apologized after a flag reportedly bearing markings similar to those of the Nazi SS was displayed during a recent match.

Gamba supporters were seen waving a flag with the markings "very similar to the symbol" of the Nazi paramilitary organization in the form of a double S during a game on Sunday, team spokesman Kenji Okunaga said Friday.

The incident came after the J-League in 2014 ordered the Urawa Red Diamonds, one of its teams, to play in an empty stadium as punishment for a "Japanese only" banner that fans displayed during a match in Tokyo.

The J-League prohibits displays of any kind linked to political ideology, religion or race and also bans racial and other forms of discrimination.