American lawyer Michael Garcia has resigned from his role as lead investigator of FIFA's ethics committee.

FIFA rejected an appeal by Garcia on Monday over the handling of his investigation into the controversial 2018 and 2022 World Cup bids by Russia and Qatar.

The American, who was appointed two years ago, lodged an appeal after disagreeing with how his findings were presented by chairman of the Independent Ethics Committee Hans-Joachim Eckert.

While Eckert claimed that any wrongdoing during the bidding processes was of "very limited scope", Garcia insisted that the published version of his report contained "incomplete and erroneous representations of the facts and conclusions".

"No independent governance committee, investigator, or arbitration panel can change the culture of an organisation," Garcia said on Tuesday. "It is the lack of leadership on these issues within FIFA that leads me to conclude that my role in this process is at an end."

FIFA officials, including president Sepp Blatter, are currently in Marrakesh for the Club World Cup.