The IAAF must have been aware of the extent of doping in track and field, with corruption "embedded" in the sport's world governing body, the second part of a report by an independent commission established by the World Anti-Doping Agency has concluded.
International track and field was hit by one of the biggest sporting scandals last November when the first part of the commission's report made allegations of state-sponsored doping in Russia.
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The All-Russia Athletic Federation subsequently was suspended by the IAAF and the WADA commission on Thursday said that the sport's governing body, including former president Lamine Diack, had to have known about the doping.
"The disruption of the federation emanated from the very top — the president, Diack," professor Richard McLaren, a member of the three-man commission, said in a news conference in Munich.
Diack's successor, Sebastian Coe, insisted that the IAAF was not guilty of covering up Russian athletes' positive drugs tests amid published reports that the organization was aware of doping in the country as long ago as 2009.
However, the second part of the independent commission report stated: "The corruption was embedded in the organization.
"It cannot be ignored or dismissed as attributable to the odd renegade acting on his own.
"The IAAF allowed the conduct to occur and must accept its responsibility. Continued denial will simply make it more difficult to make genuine progress."
The report also stated: "It is increasingly clear that far more IAAF staff knew about the problems than has currently been acknowledged.
"It is not credible that elected officials were unaware of the situation affecting athletics in Russia.
"If, therefore, the circle of knowledge was so extensive, why was nothing done? Quite obviously, there was no appetite on the part of the IAAF to challenge Russia.
"In the 2013 timeframe, the fact that the World Championships were to be held in Russia was a factor, since the IAAF wants to ensure that its World Championships are successful, even if only to validate its own choice of the host country.
"Focus, therefore, may understandably be on making sure that pre-award promises are kept, that ticket sales are high, that broadcasters and sponsors are satisfied, and so forth.
"But these are one-off events and the problems continue unabated, both before the awards [when commitment to good conduct may be more easily obtained] and after the World 47 Championships [when assessments can be made absent short-term considerations such as the World Championships]."
Diack is being investigated by French authorities as part of a corruption inquiry, while a wanted-man appeal for his son, Papa Massata Diack, was posted on Interpol's website on behalf of French police Thursday over allegations of corruption and money laundering.
Papa Massata Diack, a former IAAF marketing consultant, was one of three senior IAAF officials to be banned for life by track and field's' world governing body last week for a breach of its Code of Ethics.
The 50-year-old was charged after being subject to disciplinary hearings over his alleged involvement in a doping cover-up relating to London Marathon winner Liliya Shobukhova of Russia.
Independent commission chairman Dick Pound on Thursday claimed Coe, despite coming under heavy scrutiny as details of the IAAF's widespread issues emerge, remains the best candidate to reform the organization.