IOC's Bach says he didn't know how complex it would be to stage the Games

International Olympic Commission (IOC) President Thomas Bach said he did not know "how complex this would be" to stage the Tokyo Games, which start later this week.

"I can admit we did not know how complex this would be. The only certainty we had was rather than cashing in on the insurance, we would have to invest much more to make this Olympic games possible," Bach told members of IOC.

Bach also said World Health Organization Director-General Tedros Adhanom Ghebreyesus would be in Tokyo on Wednesday and deliver a speech to IOC members.