Rangers are investigating after a video on social media showed supporters chanting a racist song about Celtic forward Kyogo Furuhashi.
In response to the footage, which emerged on Sunday, a Rangers spokesperson said: "Rangers condemns all forms of racism and discrimination.
"Those who indulge in such behaviour are not representative of our club or the loyal support who have stood by us through thick and thin.
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"We are currently investigating to identify the individuals involved."
Celtic tweeted on Sunday night to condemn the "sickening and pathetic" footage, adding they would provide Furuhashi with their "full support".
"If reports are accurate then such sickening and pathetic racist behaviour directed towards Kyogo Furuhashi deserves absolute condemnation," the tweet said.
"Unfortunately, a number of Celtic players in recent years have suffered similar racist abuse.
"As a club open to all, we stand firmly against racism in all its forms and we will give Kyogo our full support. All stakeholders must work together in tackling all forms of bigotry."
Police Scotland have confirmed it is in talks with Rangers over the social media video.
"Police Scotland is aware of a video circulating on social media and officers are liaising with the club to make relevant enquiries," read a statement released on Monday.
Furuhashi joined Celtic from Japanese side Vissel Kobe this summer and scored a hat-trick on his home debut against Dundee earlier this month.
The Japan international has five goals in seven games so far this season.
Rangers are set to host Celtic in the first Old Firm game of the season next weekend at Ibrox, live on Sky Sports.
The Hoops will be without supporters after Rangers withdrew the offer of around 700 away tickets for the fixture.
The champions made the decision after Celtic were unable to guarantee that a similar arrangement would be in place for the return fixture at Parkhead in January.