International Cycling Union president Pat McQuaid has dismissed an anonymous leaked dossier alleging corruption at the UCI as "gangster politics".
And McQuaid has called on his election rival Brian Cookson to speak out against the allegations as well, the latest move in an increasingly bitter contest.
Cookson, the British Cycling president, is challenging McQuaid for the leadership of cycling's governing body.
However, McQuaid has not been nominated by his home country, Ireland, or his place of residence, Switzerland, and wants the UCI congress to approve a rule change allowing him to be nominated by Thailand and Morocco.
And he has now written an open letter to all of the national cycling federations, defending himself against the corruption allegations.
McQuaid challenge to Cookson
"The claims in this so-called dossier are a complete fabrication," the letter read. "They are totally untrue and are not supported by a scintilla of evidence.
"The UCI Ethics Commission has already tried to investigate this dossier. This is a scurrilous and libelous attack on my character. This is not democracy, this is gangster politics.
"If Brian Cookson does not now condemn these tactics utterly, then we can only assume that he supports them.
"I am proud to stand before you as a candidate in this election. I am proud to present you with a clear choice of leadership for the coming four years.
"I will be prouder still if you choose me as your next president at Congress this month. But, if you do not, I will accept your choice with good grace and I will leave Florence with my head held high.
"I will know that I have given my all to the UCI over the past eight years and that I have done everything possible to protect our democratic process. I challenge Brian Cookson to say the same thing."
Cookson has not yet responded to McQuaid's letter, but had previously called for an investigation.
"These allegations, which appear to be similar to those made to the UCI Management Committee in June, are clearly very serious," he said in a statement.
"For the good of the UCI and cycling, they should be immediately and thoroughly investigated by the relevant authorities. I hope that this matter can be fully resolved before the UCI congress on September 27."
The UCI Congress will elect the world governing body's next president at the World Road Championships on September 27 in Florence, Italy.