IAAF deputy general secretary Nick Davies has temporarily resigned from his post pending an investigation into allegations he planned to delay naming Russian athletes involved in doping.
French newspaper Le Monde recently published a leaked email from Davies to then marketing consultant Papa Massata Diack on July 19, 2013 - 22 days before the start of the World Championships in Moscow.
In the email, Davies expresses his need to "sit down" with the anti-doping department in order to "understand exactly what Russian 'skeleton' we have still in the cupboard regarding doping".
Davies goes on to say that the IAAF needed to be "smart" about releasing the names of those implicated.
Shortly after the email leak Davies - promoted by IAAF president Sebastian Coe this year - denied attempting to cover up doping.
However, he now faces an investigation from the governing body and a widely circulated statement on Tuesday read: "In order to demonstrate that I am willing to have all allegations of unethical behaviour on my part in 2013 properly and fairly investigated I have referred my emails to Papa Massata Diack in 2013, my statements and the circumstances of the emails to the IAAF Ethics Board.
"I have decided to step aside from my role with the IAAF until such time as the Ethics Board is able to review the matter properly and decide if I am responsible for any breach of the IAAF Code of Ethics."
Diack was the subject of an IAAF hearing last week after being charged with breaches of its Code of Ethics and is said to have been "very active" in an alleged "system of corruption" that attempted to cover up suspected doping by blackmailing athletes.
The All-Russia Athletic Federation was suspended by the IAAF last month amid allegations of state-sponsored doping in a report from an independent commission set up by the World Anti-Doping Agency.