A former governor of Rio de Janeiro says he helped pay a $2m (£1.6m) bribe to secure the Olympic Games for the Brazilian city in 2016.
Sérgio Cabral told a judge the payment was made to secure votes in the decision-making meeting in 2009.
He said that Carlos Nuzman, then the chairman of the Brazilian Olympic Committee, handled the negotiations.
In 2017, Mr Nuzman was arrested amid an investigation into the alleged vote-buying scheme. He denies wrongdoing.
Cabral is currently serving a 200-year sentence for several corruption cases.
On Thursday, he said the then-president of the International Association of Athletics Federations (IAAF), Senegal’s Lamine Diack, also served as intermediary in the alleged deal.
Mr Diack is to stand trial in France, having been arrested there in 2015. He has been accused of taking payments for deferring sanctions against Russian drugs cheats. He has previously denied wrongdoing, but has not yet responded to the latest allegations.
Both Mr Diack and Mr Nuzman were suspended from their roles, and later resigned.
Cabral also said Brazil’s then-president, Luiz Inácio Lula da Silva, had been informed after the money had allegedly changed hands.
Lula’s lawyers have said this is untrue. He has been jailed in a separate corruption case.
Why has this come out now?
Ongoing criminal investigations into alleged bribery – led by prosecutors in Brazil and France – have already implicated Mr Nuzman, Mr Diack and his son, and then-IOC executive board member Frank Fredericks.
However, no leading officials have admitted involvement until now.
Cabral, who served two terms as Rio state governor from 2007 to 2014, spoke out during a hearing requested by his new defence team as he seeks a plea deal.
He hopes the information might reduce the lengthy sentences faced by him and his wife, Adriana Ancelmo.
They were jailed in connection with a corruption case involving the construction company that built the Rio Games.
Several high-powered Brazilian executives and politicians have recently reduced their sentences through plea bargains and giving evidence against others.
Who else was named?
Cabral told investigators that his bribe had been aimed at winning the support of nine of the committee’s 95 members.
He implicated several top athletes who had voting rights. Olympic gold medallists Sergey Bubka and Alexander Popov have both since denied taking a bribe, and said they were considering suing for defamation.
Mr Popov, a Russian former swimmer, released a statement via social media, saying he did not vote for the city, or participate in any negotiations.
Mr Bukba, a Ukrainian pole-vault champion, posted a series of tweets, in which he said he completely rejected “all the false claims made by the former Rio State governor”.
The ex-governor also said the money was provided by businessman Arthur Soares, one of his close friends, and transferred to Diack’s son, Papa Massata, who has previously denied wrongdoing.
Brazilian prosecutors charged Mr Soares – nicknamed King Arthur – for alleged involvement in bribery in 2017. He moved to the US during the investigations.
What does the IOC say?
The International Olympics Commission (IOC) says its chief ethics officer is following up on the latest allegations.
The IOC implemented a series of reforms in 2014. On Friday, it said: “The IOC is fully committed to address any issues, including those which happened before the far-reaching reforms.”
Rio won its Olympic bid in 2009, beating co-finalists Chicago, Madrid and Tokyo. It was the first South American city ever to host the Games.
In January, news broke that the bidding process for Tokyo 2020 was also under investigation by French authorities.
The Japanese government has always insisted its Tokyo bid was clean.