Austria midfielder Marcel Sabitzer was struck by an item seemingly thrown by Turkey fans during the second half of their Round of 16 defeat in Leipzig.
With Austria trailing in the hunt for a quarter-final place, Sabitzer repeatedly had several items hurled in his direction as he went over to take corner kicks in front of a section of Turkey supporters.
Having earlier had cups tossed at him, a smaller item appeared to hit Sabitzer, who fell to the floor in pain. Soon after, a number of Turkey players went over to the corner to attend to the stricken Austria captain, before talking to the crowd in an apparent attempt to get spectators to stop.
A large collection of cups were cleared off the pitch during the second half of the last-16 encounter, which Turkey edged 2-1 to set up a quarter-final against the Netherlands.
Euro 2024 has been pockmarked with incidents of crowd trouble, with Uefa handing out over €1m in fines for various infractions.
Turkish supporters were involved in pre-match scuffles with fans of Georgia before the two sides met in Dortmund during the group stages.
The Scottish Football Association, meanwhile, were fined €9,000 (£7,640) for two incidents of fans “throwing objects” earlier in the tournament.
A double from defender Merih Demiral was enough to take Turkey through to the last eight at a major tournament for the first time in 16 years.