WARSAW -- Five people were arrested after trouble at the Champions League match between Legia Warsaw and Borussia Dortmund on Wednesday.
Around 30 minutes into the game, which ended in a 6-0 win for Dortmund, fans stormed the block next to the away section.
Footage showing one man wearing a Legia mask spraying pepper spray into the area. There were no reports of injuries.
Seweryn Dmowski, Legia's adviser to the board, told ESPN FC the club had already taken action against many of those involved.
"A group of our fans moved to the other sector of the stadium. We have identified 70 people who we consider to have been involved," he said.
"We are verifying each of them individually. So far around 15 have been given a banning order for two years."
He said that, under the club's current chairmanship, those fans would not be readmitted even after their bans had expired, describing them as "bandits."
Dmowski told ESPN FC that the five people arrested had been detained overnight and on Thursday morning.
"Police and security reacted very well, and their task was to prevent a confrontation," he said.
Legia fans reportedly aimed offensive chants at Dortmund fans, but Dmowski denied that any chanting had been anti-Semitic.
"We hope and we count on that we will only be treated for just what we did [the storming of the area next to the away section]," he said.
"Our very important task to let everyone know that there is no acceptance of racism. We will take consequences for what we've done. But we wouldn't like to take consequences for what we haven't done."
However, observers from anti-discrimination group FARE wrote on Twitter they had witnessed anti-Semitism at the match and had sent a report to UEFA.
Dortmund said they did not want to comment on the incidents and told ESPN FC that UEFA would review what had happened.