Simone Biles has withdrawn from two apparatus finals at Tokyo 2020 ©Getty Images

American star Simone Biles has withdrawn from tomorrow's vault and uneven bars finals at the Tokyo 2020 Olympic Games as she continues to prioritise her mental health.

USA Gymnastics confirmed the four-time Olympic champion would not compete in the two events "after further consultation with medical staff".

The 24-year-old had pulled out of the team final on Tuesday (July 27) and the individual all-around competition on Thursday (July 28) to focus on her mental health.

Biles is the defending champion in the vault and has qualified for all four apparatus finals at Tokyo 2020.

A decision has not yet been made on her participation in the women's floor and balance beam finals, scheduled for Monday (August 2) and Tuesday (August 3), respectively.

"Today, after further consultation with medical staff, Simone Biles has decided to withdraw from the event finals for vault and the uneven bars," USA Gymnastics said in a statement.

"She will continue to be evaluated daily to determine whether to compete in the finals for floor exercise and balance beam. 

"MyKayla Skinner, who had the fourth highest score in vault during qualifications, will compete in vault finals for the US alongside Jade Carey, who finished with the second highest score.

"We remain in awe of Simone, who continues to handle this situation with courage and grace, and all of the athletes who have stepped up during these unexpected circumstances."

Simone Biles cheered on her fellow gymnasts during the women's all-around final ©Getty Images
Simone Biles cheered on her fellow gymnasts during the women's all-around final ©Getty Images

Biles, considered the greatest gymnast of all time, admitting she was still struggling in a training video posted on Instagram yesterday.

The 19-time world champion said she had been having problems "literally on every event, which sucks".

"This was not happening before I left the USA. It randomly started happening after prelims competition the very next morning," Biles said in the video.

"I seriously cannot comprehend how to twist. 

"Strangest and weirdest feeling...it's honestly petrifying trying to do a skill but not having your mind and body in sync."

Biles' decision not to participate in both the team and individual finals had drawn widespread praise, although she has also been subjected to abuse on social media.

She cheered on her fellow gymnasts in the women's all-around final, won by compatriot Sunisa Lee on Thursday (July 29).