Anita Alvarez was not breathing after her performance in the free solo synchronized swimming final, and sank to the bottom of the pool.

Andrea Fuentes then jumped into the water to rescue her.

"We were very scared. I had to jump because the rescuers weren't doing it," Fuentes told Spanish newspaper Marca.

Fuentes, wearing shorts and a T-shirt, descended to the bottom of the pool and lifted Alvarez to the surface before receiving help to carry the distressed swimmer to the edge of the pool.

"I was scared because I saw that she was not breathing, but now she is fine," reassured Fuentes.

The coach of the American artistic and synchronized swimming team Andrea Fuentes (d) comes to save her swimmer Anita Alvarez who lost consciousness during the World Swimming Championships in Budapest on June 22, 2022 Oli SCARFF AFP

A stretcher carried Alvarez to the poolside medical center, leaving teammates and spectators in shock.

The US swim team released a reassuring statement about Alvarez's health.

Quadruple Olympic medalist, Fuentes explained to a Spanish radio that her swimmer had become unwell due to the effort exerted during her performance.

"She only had water in her lungs, once she started breathing again everything was fine," she added.

"I felt like it was a whole hour. I said things weren't right, I yelled at the lifeguards to get in the water, but they didn't hear what I said or they didn't understand".

"She was not breathing (...) I went as fast as I could, as if it were for an Olympic final", she also told.

According to his coach, Alvarez planned to rest Thursday and still hoped to compete in the team event on Friday after medicals.

The coach of the American artistic and synchronized swimming team Andrea Fuentes (l) holds the head of her swimmer Anita Alvarez who lost consciousness during the World Swimming Championships in Budapest on June 22, 2022 Peter Kohalmi AFP

At 25, Alvarez is taking part in his third World Championships.

She had already lost consciousness several times during the qualifying rounds at the Olympic Games last year in Barcelona.

© 2022 AFP