Leeds fans Christopher Loftus and Kevin Speight were stabbed to death during street clashes the night before Leeds played Turkey's Galatasaray in the UEFA Cup in April 2000.
Millwall said in a club statement: "Millwall Football Club strongly condemns the inflammatory behaviour of certain individuals who waved Turkish fans and shirts during Saturday's match with Leeds United.
"The club deplore these actions, which were were totally unacceptable and detracted from what should have been a memorable game for both Millwall and Leeds United supporters.
"Following incidents during the match, four people were ejected from the ground on Saturday for waving Turkish flags and have been banned indefinitely by Millwall FC. Six Leeds United supporters were also arrested."
Millwall chief executive Andy Ambler added: "We have already identified a number of people and will continue to work tirelessly, using all possible evidence to identify and prosecute perpetrators."
Source: PA
