Zenit St Petersburg are likely to face UEFA sanctions after crowd trouble marred their Champions League match with APOEL Nicosia on Wednesday evening.
Referee Felix Brych stopped play twice during the 0-0 draw as lit flares were thrown onto the pitch.
"Zenit consider unacceptable a situation when the actions of some individual supporters have a negative effect on the course of a game and could lead to heavy disciplinary sanctions including a forfeit," read a statement on the Russian club's official website.
"In the next few days the club and police, with the help of UEFA and the Russian FA, will conduct an investigation and will issue much tougher rules in regards to searches of fans before entering the stadium."
UEFA said that they would gather the relevant evidence before they decided on what action to take.
"We're in a process of collecting information in relation to the events at the game and when we have all the facts we will make a decision," said a spokesman.
APOEL's goalless draw meant that they were the first ever team from Cyprus to make it through to the last 16 of the competition.