Qatar's bid for the 2022 World Cup was categorised as a "high security risk" in a briefing weeks before the voting process, according to a report.
Excerpts from the report - seen by BBC Sport and published by the Sunday Times - warned Fifa executives of Qatar's proximity to countries with an "al-Qaeda presence".
It said that Qatar's intentions to stage Fifa World Cup games in a "highly concentrated" area meant it faced cancellation in the event of a major terrorism incident.
The briefing was prepared by South African security consultant Andre Pruis on the instruction of Fifa's general secretary Jerome Valcke.
It examined the strengths and weaknesses of each bidding nation.
However, Pruis was given just one day to complete his report and commented ahead of its conclusion: "The reading of the material posed a mammoth challenge."
In his security briefing, Pruis wrote: "The fact that 10 of the 12 stadiums are located in a 25-30km radius will not only create an overlapping of certain security zones but will also cause major crowd management and traffic problems before and after matches."
The latest documents published by the Sunday Times came hours after the organisers of Qatar 2022 robustly defended the bidding process against what it claims are "baseless allegations".
In a statement, Qatar 2022 says reports of impropriety around the voting for the 2018 and 2022 World Cup tournaments are a "flagrant attempt to prejudice an ongoing independent investigation".
A Fifa ethics committee led by lawyer Michael Garcia is looking into the 2018 and 2022 bidding processes.
Part of his remit is examining allegations that Mohamed Bin Hammam was behind a $5m "slush fund" that paid football officials in return for their backing of Qatar's World Cup bid.
The Sunday Times also makes several further allegations about the nature of the relationship between Mohamed Bin Hammam and Qatar 2022 officials.
Qatar 2022 said it "strictly adhered" to Fifa's rules, had "nothing to hide" and "worked harder than anyone else".
Russia, who won the right to stage the 2018 World Cup, was given the second highest security rating according to the document.