Glasgow - Hearts have pledged to probe allegations that Rangers striker Alfredo Morelos was racially abused after scoring the equaliser in Sunday's 1-1 draw at Tynecastle.
Colombian striker Morelos was allegedly targeted as he celebrated in front of the Hearts supporters.
Hearts promised to ban any fan found guilty of racism and said: "The club is aware of an incident of alleged racism and is currently investigating it.
"It goes without saying that Heart of Midlothian Football Club utterly condemns any form of racism and any individuals found guilty of such an offence will face an indefinite ban from Tynecastle."
It is the latest outbreak of racism in football following several incidents this week.
England players were subjected to monkey chants and Nazi salutes from Bulgaria fans, with the Euro 2020 qualifier twice halted due to the incidents in Sofia.
On Saturday, non-league Haringey walked off the pitch after two of their players were allegedly racially abused and spat at during an abandoned FA Cup tie against Yeovil.
Meanwhile, Bristol City are investigating reports of racist language being used by their fans during their Championship game at Luton.
The Morelos incident overshadowed Rangers' failure to move back to the top of the Scottish Premiership.
Steven Gerrard's side would have gone back above Celtic into first place with a win over Hearts.
But the hosts took a first-half lead through Japanese midfielder Ryotaro Meshino and although Morelos equalised with his 15th goal of the season before the break, the Glasgow club couldn't find a winner.
That meant Celtic held onto pole position -- because they have scored more goals than Rangers -- following their 6-0 thrashing of Ross County on Saturday.
"I don't think we performed well enough to win the game, that's for sure. I certainly see it as two points dropped right now," Gerrard said.
"We never started the game well enough. I thought we were poor in the opening exchanges and lucky not to be 2-0 down.
"It's an individual error again that's cost us. Even going forward, today we just weren't at it. It's a frustrating day."