Awarding the 2022 World Cup to Qatar may well have been "a mistake", FIFA president Sepp Blatter said for the first time on Monday.

Staging the tournament in the Middle East has caused much controversy because if it is held over its traditional dates in the middle of the year, players will have to contend with searing 50 degrees Celsius heat.

Calls to move the World Cup to later in the year, during the European winter, have also been unpopular as it will cause major disruption to domestic league competitions in countries such as Spain, England, Italy, Germany and France.