Olympiacos and Zenit St Petersburg have both been handed partial stadium closures by UEFA following trouble involving their respective fans.
Olympiacos will have to close the lower tier of their north stand when they host Manchester United in the first leg of their last-16 Champions League tie on February 25 after supporters were found guilty of racist conduct during a recent match against Anderlecht.
The Greek side have been fined an additional €30,000 (£25,380).
Meanwhile, Zenit will also be forced to shut a section of their stadium when Borussia Dortmund visit on the same night following disruptions in their recent game versus Austria Vienna.