Romanian gymnast Ana Barbosu will be awarded the Olympic floor exercise bronze medal, after it was taken away from her following an appeal from the United States.

The International Olympic Committee made the announcement on Sunday, one day after the Court of Arbitration for Sport ruled that the request by the American team to re-evaluate Jordan Chiles' score was lodged four seconds after the one-minute deadline.

The review, which went ahead at the time, upgraded Chiles to bronze from fifth, behind Brazil's winner Rebeca Andrade and fellow US gymnast Simone Biles.

But it was a devastating blow for Barbosu, who thought she had bagged bronze and was already celebrating with the Romanian flag.

"I can barely express my emotions, I can't believe it," Barbosu said after learning she was awarded her country's only gymnastics medal in Paris.

"When I heard the news, I was afraid it wasn't true, and once I was sure, I hugged my parents and called everyone who had helped me."

A devastated Chiles took to Instagram, posting four broken hearts, adding: "I am taking this time and removing myself from social media for my mental health thank you."

Biles, who trains with Chiles, and won team gold with her in Paris, added: "Sending you so much love Jordan. Keep your chin up Olympic champ! We love you!" (Additional reporting by AFP)