Maribor, September 14: Spartak Moscow face Uefa censure after a flare was fired on to the pitch by their fans during their 1-1 Champions League draw at Maribor in Slovenia.
The crowd trouble comes as concerns grow about hooliganism at next year's World Cup finals in Russia, reports the Guardian.
During a goalless first half, filled with missed opportunities, a flare was fired from the Spartak supporters massed at one end of the ground towards the centre of the pitch, landing close to the referee Deniz Aytekin, who was standing in the centre circle.
It is far from the first time that Spartak's fans have overshadowed the team's efforts.
Spartak were fined a total £8,500 by the Russian football union after racist slogans were displayed on a banner and violence marred a league match against Arsenal Tula in April 2015.
Spartak, who welcome Liverpool to Moscow in their second group game in two weeks' time, were held to a 1-1 draw after Damjan Bohar's 85th-minute equaliser for the hosts.