FIFA has announced that it has concluded an internal investigation after allegations of corruption and criminal wrongdoing.

World football's governing body launched the probe through United States law firm Quinn Emanuel in the wake of the corruption scandal that engulfed it in 2015.

FIFA has compiled documentation detailing more than 20,000 pieces of evidence after a 22-month inquest, which involved a number of witnesses being questioned and the analysis of more than two and a half million documents.

The evidence has been submitted to Swiss authorities as part of the ongoing US-led criminal investigation into allegations of bribery and money laundering involving several former FIFA officials.

"FIFA announced today that it has completed the internal investigation it began in June 2015 after the Office of the Attorney General of Switzerland (OAG) and the United States Department of Justice (DOJ) announced investigations into allegations of criminal misconduct, bribery and corruption in world football," a statement read.

"During the course of FIFA's 22-month investigation, more than 2.5 million documents were reviewed and numerous key witnesses were interviewed. Using the evidence obtained from the document reviews and witness interviews, FIFA's external counsel prepared written investigative reports on issues of primary concern to the Swiss and US authorities.

"These reports, which total more than 1,300 pages and include more than 20,000 pages of exhibits, have been shared with the Swiss authorities. The OAG has acknowledged FIFA's close and consistent cooperation. FIFA understands and has agreed that the reports will also be made available to the US authorities."

FIFA president Gianni Infantino said: "FIFA committed to conducting a thorough and comprehensive investigation of the facts so we could hold wrongdoers within football accountable and cooperate with the authorities.

"We have now completed that investigation and handed the evidence over to the authorities, who will continue to pursue those who enriched themselves and abused their positions of trust in football. FIFA will now return its focus to the game, for fans and players throughout the world'."

FIFA says it is unable to release more details on its findings given that the OAG and DOJ criminal investigations are ongoing.

It added that "the findings have been used to make specific changes to FIFA's governance, compliance and finance functions". A report will be released in April to summarise the proposed changes.