UEFA was left with more security questions to answer at Euro 2016 after Croatia fans hurled flares onto the pitch forcing a halt to their clash with Czech Republic on Friday.
A series of firecrackers were thrown from the Croatian end late on in their 2-2 draw, forcing referee Mark Clattenburg to temporarily pause the Group D action in Saint-Etienne.
A member of the stadium staff sent to clear the flares was almost struck as one of the pyrotechnics exploded next to him.
And, while Croatia's players sought to calm their fans, there were ugly scenes in the stands as some of the country's supporters scuffled with each other.
Fighting continued even after play resumed, following around a five-minute break, with stewards deployed to break up the trouble.
The scenes overshadowed late drama on the pitch, as an injury-time Tomas Necid penalty rescued an unlikely draw for the lacklustre Czechs.
The incident is the latest to put security measures under the spotlight at the tournament, with Russia handed a suspended disqualification following trouble in the stands in their Group B opener against England in Marseille - which was preceded by a series of flares being let off.
UEFA also confirmed it would investigate Portugal fans after a firecracker was apparently lit among their supporters during the 1-1 draw with Iceland, also in Saint-Etienne, on Tuesday.