The former head of global track and field, Lamine Diack, told his corruption trial on Thursday he had agreed to delay and stagger bans for Russian athletes caught doping for the sake of the sport's "financial health".
But Diack, who headed the International Association of Athletics Federations (IAAF) for 16 years, denied he had known officials from his federation had directly or indirectly asked Russian athletes for hundreds of thousands of euros to hush up their cases.
Diack, an 87-year-old Senegalese, told a court in Paris it was his decision to delay bans after 23 Russian athletes failed tests in 2011.
"It was mainly for the financial health of the IAAF," he said.
"The financial health of the IAAF had to be safeguarded and I was prepared to make that compromise."
Diack has admitted that doping bans were delayed in order to allow Russian athletes to compete in the 2012 London Olympics and the world championships in Moscow the following year.
The aim was to prevent the cases derailing talks with prospective Russian sponsors including state-owned bank VTB and the RTR broadcaster.
Diack, who was once one of the most powerful leaders in Olympic sport, is being tried for corruption, money laundering and breach of trust. The charges carry a maximum sentence of 10 years in prison.
French prosecutors say Diack directly or indirectly demanded 3.45 million euros ($3.9 million) from Russian athletes in order to have their names cleared in an illicit system known as "full protection".
The delay in imposing bans allowed some of the Russians to win medals at the London Olympics.
- Son 'behaved like a thug' -
Diack denied being aware that Russian athletes, including runner Liliya Shobukhova, had been asked to pay hundreds of thousands of euros to benefit from the protection.
German broadcaster ARD has revealed that Shobukhova paid 450,000 euros, allegedly to have her blood passport case delayed in order to compete in the London Olympic marathon.
Diack told the court he had been "flabbergasted" to learn from prosecutors that his son Papa Massata Diack had got involved in the doping cases.
He said that if what the prosecutors had told him was true, "(Massata Diack) behaved like a thug".
Massata Diack, who worked as a marketing consultant for the IAAF, is among the co-accused but will not appear at the trial. Despite two international arrest warrants issued by France, the Senegalese authorities have refused to extradite him.
Prosecutors also allege that Diack senior obtained $1.5 million from Russia to help fund Macky Sall's successful campaign for the 2012 Senegal presidential election in return for the doping cover-up.
Diack though said that when he visited Moscow in 2011 to receive an award from then-Russian president Dmitri Medvedev, "(the Russians) asked if I wanted to be a candidate" in the election.
He admitted however that the sum of $1.5 million had been mentioned in discussions with the Russian sports minister at the time, Vitaly Mutko, without giving further details.
Diack later denied having ever asked for money to fund Sall's campaign, something he added he had not supported.
"I did not ask for money from anyone," Diack replied when asked by his lawyer Simon Ndiaye.
"If I was to ask for money from the Russians, I'd have asked (Vladimir) Putin, not Mutko."
Also on trial are the IAAF's former anti-doping chief Gabriel Dolle, who is accused of accepting bribes, and Diack senior's legal advisor Habib Cisse, suspected of acting as an intermediary between the federation and Russian track and field authorities.
Two other defendants are absent from the trial.
Valentin Balakhnichev, a former top Russian track and field official and IAAF treasurer, is accused of "giving and receiving bribes" and "aggravated money-laundering".
Alexei Melnikov, formerly Russia's chief distance running coach, is accused of "receiving bribes".