TOKYO (AP) — IOC vice president John Coates expressed concern Thursday over payments made to a Singapore firm which have entangled Tokyo's winning bid for the 2020 Olympics in a bribery investigation.

Leaders of Tokyo's bid have admitted making payments of 2.8 million Singapore dollars ($2 million) to a Singaporean firm headed by Ian Tan Tong Han, a close associate of Papa Massata Diack, the son of former IAAF President Lamine Diack, who is facing corruption charges in France.

French prosecutors are looking into the payments as part of an investigation of Diack. The Japanese Olympic Committee is also investigating the matter.

The allegations of bribery have shocked many in Japan.

"We share the same concerns as the Japanese public does about corruption," said Coates, who heads the IOC's coordination commission for the Tokyo Games. "I think that should be clear from our president (Thomas) Bach and the executive board's zero tolerance approach whether it's in regard to doping or corruption in the bidding process."

JOC president Tsunekazu Takeda, who headed Tokyo's bid team, insists the payment was for legitimate consultancy work and not made with the anticipation that the money would lead to Diack.

The allegations of bribery are the latest blemish on Tokyo's preparations for the 2020 Games.

Tokyo defeated Istanbul 60-36 in the final round of the IOC voting. Madrid was eliminated on the first ballot.

The JOC has set up a three-man investigation team probing whether there were illegal payments. The team met for the first time on Thursday.

Takeda "assured me the JOC has a full open book and the IOC looks forward to the report of that investigation," Coates said.

In testimony at Japan's parliament, Takeda did not reveal who in the bid committee met with Tan to broker the deal in the months leading up to Tokyo's victory in September 2013.

Possible wrongdoing involving Lamine Diack and the 2020 Olympic bid race was cited in a WADA-commissioned investigation of the IAAF. A footnote to a report by the WADA commission in January indicated that Diack was prepared to sell his vote in exchange for $5 million in sponsorship for the IAAF.

The report suggested that Diack dropped his support for Istanbul's bid because Turkey refused to pay, and also indicated that the Japanese did pay.

The head of Tokyo's organizing committee said the problem predates their existence.

"The organizing committee is not the bid committee," Yoshiro Mori said. "The bid committee was awarded the Tokyo games and after that the organizing committee was established and we are working with the IOC for the successful delivery of the games."

Coates was in Tokyo for a two-day inspection of the city's preparations for the games but once again the focus was on controversy.

During his previous visit to the Japanese capital, Coates was answering questions about delays to the building of the new national stadium.

Work on the stadium fell behind when the government abandoned an earlier design by architect Zaha Hadid due to spiraling costs, sending organizers back to the drawing board.

Baseball-softball, surfing, skateboarding, karate and sports climbing have been proposed for inclusion in the Tokyo program.

A final decision on which sport or sports to add will be made by the IOC session in August.

"Tokyo's proposal was submitted as a package," Coates said. "Assuming the executive board supports the sports and events as a package, they go as a package to the IOC session."