ROME (Reuters) - Italy's football league is backing a public campaign to put pressure on Egypt to find those responsible for killing Italian student Giulio Regeni in Cairo.

All Serie A teams will display a large yellow banner before their league games on April 23, 24 and 25 which will read "Truth for Giulio", a spokeswoman for the league said on Friday.

The decision poses a potential problem for AS Roma's Egyptian striker Mohamed Salah because those behind the campaign have accused the Egyptian state of being behind the murder. Egypt denies this.

La Repubblica newspaper quoted a source close to Salah on Friday as saying there was "no way he can step onto the pitch with that banner there". Other newspapers have reported that Salah might quit Roma and Italy over the murder scandal.

A spokesman for AS Roma declined to comment and the player himself was not immediately available to comment.

Third-placed Roma is due to play second-placed Napoli on April 25. "(This game) is too important for a 'diplomatic injury' to befall one of Roma's best players," la Repubblica wrote, referring to Salah, who has scored 12 league goals this season.

Regeni, 28, was in Egypt doing postgraduate research into labour movements when he vanished on Jan. 25. His body was found on Feb. 3 and an autopsy showed he had been tortured over several days before dying.

Cairo investigators initially said he had died in a traffic accident and then said he had been killed by a criminal gang. Italy has rejected both suggestions and last week recalled its ambassador from Cairo.

(Reporting by Crispian Balmer)