Simone Biles retook the gymnastics stage on Tuesday after a week's absence, electrifying the Tokyo Olympics on a day that saw world records smashed and organizers investigate Belarus's treatment of an athlete now in diplomatic protection.

The return of the American, considered by many the greatest gymnast ever, ensured a blockbuster finale for the sport at the Ariake Gymnastics Center as Biles took the bronze.

She had abruptly dropped out of the team event seven days ago, citing mental health issues and increasing global awareness of the pressures elite athletes face.