The UFC community is mourning the loss of flyweight fighter Allan Nascimento, who has died at the age of 34 following an apparent heart attack.

The promotion confirmed the heartbreaking news on Monday, revealing that Nascimento was found unresponsive after suffering what is believed to have been a heart attack in his sleep.

“This morning, Monday, August 3rd, our beloved flyweight fighter, Allan Nascimento, was found unresponsive after suffering an apparent heart attack in his sleep,” UFC said in a statement. “Despite the efforts of the responding medical team, he was pronounced deceased at the scene. Our thoughts and deepest condolences are with Allan’s family, friends, teammates, and loved ones during this incredibly difficult time.”

Known by the nickname "Puro Osso," Nascimento began his professional MMA career in 2011 with a submission victory over Thiago Silva. He trained at the renowned Chute Boxe academy alongside UFC star Charles Oliveira and earned his opportunity with the promotion after winning on Dana White's Contender Series in 2018.

Nascimento officially joined the UFC in 2021 and compiled a 4-2 record inside the Octagon. His final appearance came on June 20, when he dropped a closely contested split decision to Mitch Raposo at a UFC Fight Night event.

Across his professional career, the Brazilian amassed an impressive record of 22 wins and seven defeats.