Mixed martial arts star Allan Nascimento has died at the age of 34, the UFC has announced.
The Brazilian fighter was found unresponsive on Monday after suffering an apparent heart attack in his sleep.
"Despite the efforts of the responding medical team, he was pronounced deceased at the scene," the promotion company said in a statement.
It added: "Our thoughts and deepest condolences are with Allan's family, friends, teammates, and loved ones during this incredibly difficult time."
The UFC, MMA's leading promotion, described Nascimento, a flyweight from Sao Paulo, as "a skilled competitor and consummate professional".
Nicknamed "Puro Osso", which translates as "skin and bones", Nascimento had been with the UFC since 2021, recording four wins and two losses. His last fight was back in June, a split-decision defeat to Mitch Raposo in Las Vegas.
Nascimento had an overall career record of 22 wins and seven losses, with 16 of those victories coming by way of submission.
An 'extraordinary human being'
"Today I lost a brother that the fight game gave me," fellow fighter Charles Oliveira wrote on social media, which was translated from Portuguese.
"Thank you for always being by my side, for sharing the mats and the corner. I have nothing but gratitude for having you with me – in training, in the corner, and just hanging out. I love you, man; you're a legend."
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Chute Boxing, where Nascimento trained, paid tribute to "a warrior, a friend, a dedicated competitor, and an extraordinary human being".
It added: "Allan inspired others both on and off the mats with his determination, humility, respect, and fighting spirit.
"His presence will be missed beyond measure. Rest in peace, Allan; your name, your story, and your legacy will live on forever through our star."
(c) Sky News 2026: Allan Nascimento: UFC star dies aged 34 after suffering 'apparent heart attack' in his sleep
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