Rangers manager Steven Gerrard said he was disappointed but not surprised by reports midfielder Glen Kamara was targeted by sections of a crowd comprising mainly schoolchildren during Thursday's 1-0 Europa League defeat at Sparta Prague.
In March, Finland's Kamara had complained of being racially abused by Slavia Prague's Ondrej Kudela during a Europa League tie and the continent's football governing body UEFA banned the Czech defender for 10 games.
Kamara was jeered throughout Thursday's game at the Letna Stadium, which UEFA had initially ordered closed for the match after Sparta supporters had racially abused Monaco's Aurelien Tchouameni in a Champions League qualifier.
It later decided to allow 10,000 children to attend the game against the Scottish champions.
The jeering reached its peak in the second half when Kamara was sent off, media reports said.
"If they're facts and that's the truth, then I'm extremely disappointed, but not surprised... We need the facts, we need confirmation if that's the truth before I comment," Gerrard told reporters, adding he had not been aware during the match that Kamara had been singled out by fans.
Gerrard said more had to be done to prevent spectators from targeting players.
"Not just myself, everyone across the world is asking for more and bigger and better and more extreme punishments in terms of racism. It needs to be eradicated," Gerrard said.
"But until the powers that be do more and treat it more seriously, until that happens, we're going to be dealing with these questions for a longer time."