A former governor of Rio de Janeiro has made startling new allegations about the extent of a $2 million scheme to bribe sports officials in what became a successful effort to bring the Olympics to South America for the first time.

The ex-governor, Sergio Cabral, who is serving a 200-year prison sentence for fraud and corruption, testified on Thursday that as many as nine International Olympic Committee members had been paid off to bring the Summer Games to Rio in 2016.

He said the plan had been devised by two powerful figures in the world of international sports: Carlos Arthur Nuzman, the former head of the Brazil Olympic Committee, and Lamine Diack, who for years headed the global regulatory body for track and field.

Nuzman was charged in connection with the bribery scandal in Brazil in October, while Diack, who was arrested in France in 2015, is expected to go on trial there early next year.