A promising 21-year-old soccer player has died after jumping into a river to cool off during a scorching European heatwave that has already been linked to dozens of drownings.

Kenzo Kies was swimming with three friends in the Rhône River in Lyon, France, on Monday, June 22, as temperatures in parts of the country climbed to a blistering 104 degrees.

What began as an attempt to beat the dangerous heat quickly turned into a tragedy.

Emergency crews were called to the scene around 5:30 p.m. local time. Kies’ three friends were rescued from the water, but he was the last to be found. He was pulled from the river in critical condition and rushed to the hospital.

Doctors later declared him brain dead, according to French outlet L’Equipe. He died in the hospital, the BBC reported.

The drowning happened near Parc de la Feyssine, where swimming in the Rhône is prohibited, according to French media.

Kies played for En Avant Guingamp, a French soccer club in Ligue 2, the country’s second-highest professional division. He had joined the club last summer and was playing with the reserve team.

The club announced his death in a heartbreaking tribute on X.

“En Avant Guingamp has had the sorrow of learning of the death of Kenzo Kies, a young player with the Club,” the team wrote.

“A Guingamp native since last summer, he was playing this season with the reserve team,” the club added. “En Avant Guingamp extends its most sincere condolences to Kenzo Kies’s family as well as to all his loved ones, and offers them its full support during this painful ordeal.”

Before joining Guingamp, Kies spent years training in the youth systems of Lyon and Saint-Étienne, two well-known French soccer clubs.

Saint-Étienne also mourned the young athlete in an emotional statement released Wednesday, June 24.

“The Green Generation is in mourning,” the club wrote. “A resident of the Robert-Herbin Sports Center for seven years, a talented player and discreet young man appreciated by all, Kenzo Kies has lost his life in dramatic circumstances.”

The club added, “AS Saint-Étienne extends its most sincere condolences to his loved ones as well as to those — teammates and coaches alike — who shared a piece of his Stéphanois journey. Kenzo, in the corridors of L’Étrat, no one will ever forget you.”

Kies’ death comes as France battles a deadly heatwave that has pushed people toward rivers, lakes and other bodies of water in search of relief.

French Prime Minister Sébastien Lecornu said 40 people have drowned in heatwave-related incidents since Thursday, June 18. Many of the victims were young people, according to French outlet Libération.

Sports and Youth Minister Marina Ferrari warned that swimming in dangerous or unsupervised areas during extreme heat can turn deadly in moments.

“It’s not something to be taken lightly, going swimming in unsupervised areas during a heatwave,” Ferrari told French radio, according to the BBC.

For Kies’ teammates, coaches and loved ones, the tragedy has left a young life and promising soccer career cut short far too soon.