Four members of the Algerian football squad were injured when their team bus came under attack from stone throwers as it arrived in Cairo.
Algeria and Egypt, who are bitter football rivals, play a World Cup qualifying match in Cairo on Saturday.
Egyptian police have denied that anyone was injured in the incident, and the press accuses the Algerians of fabricating the whole thing.
But a Fifa official has said three players might have to miss the match.
A reporter for Algerian radio said that about 200 young people appeared just as the team arrived at a Cairo hotel and launched a hail of stones at the bus. Algerian radio has been reporting that three players were injured.
'Blood on the floor'
The Algerian sports minister, Hachemi Djiar, is reported to have described the incident as "very regrettable".
These weren't superficial injuries. With the stitches needed, we will have to see if these players can play
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