Rangers have been ordered to close a section of Ibrox when they host Legia Warsaw after Uefa ruled some of their fans were guilty of “racist behaviour” – specifically, sectarian chants.

At least 3,000 seats will be empty for the Europa League play-off second leg next Thursday after the decision by Uefa’s control and disciplinary body.

The offending chants came during Rangers’ 6-0 home victory against St Joseph’s of Gibraltar in the first qualifying round on 18 July. Uefa added that Rangers must display a banner carrying the wording “#EqualGame”, with the Uefa logo on it, in the closed section.

The Glasgow club, who drew 0-0 in Poland on Thursday, issued a warning to fans to behave in the wake of the sanctions. A statement read: “Our supporters have been asked repeatedly by the club to refrain from indulging in this, and other forms of unacceptable behaviour. Sadly, the warnings have fallen on deaf ears and the actions of this minority will cause the club and the majority of good and decent Rangers supporters to pay a heavy penalty.

“The area, or areas, to be closed will be announced in due course and the club will do its best to restrict the impact to supporters.

“Unfortunately a significant number of supporters, innocent of any wrongdoing, will be unable to attend next week’s match. This is deeply regrettable to all at the club and we hope that the guilty parties, who attracted the attention of Uefa, might reflect on the damage their unacceptable behaviour is causing Rangers and their fellow supporters.

“If any individual supporter is unable to behave in a civilised manner then please stay away from Ibrox and our club. You are harming Rangers and that is something a genuine supporter would never wish to do.”

The Rangers chairman, Dave King, reiterated the club’s message to fans. “Rangers has players and supporters from many religions, cultures and backgrounds but we are one and the same when we gather to support our club,” he said. “If any supporter cannot accept that then Rangers is not the club for them.”

Steven Gerrard stated after the first leg that his players needed “the four sides of the ground next week to get the place jumping and rocking” but his team will be denied a capacity crowd.