Brazilian fighter Allan Nascimento was found dead in his sleep after a suspected heart attack, the UFC has reported.

Ultimate Fighting Championship (UFC) fighter Allan Nascimento has died at the age of 34 after suffering an apparent heart attack in his sleep.

The mixed martial art (MMA) body posted the news about the Brazilian’s passing late Monday on their website.

“This morning, Monday, August 3rd, our beloved fighter and exemplary flyweight, Allan Nascimento, was found unresponsive after suffering an apparent heart attack in his sleep,” the UFC statement read.

“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.”

Nascimento, who remained a Sao Paulo resident throughout his life, leaves behind a wife and two children.

The last fight for the flyweight came in June, when he was defeated by Mitch Raposo in a split decision.

Nascimento fought out of Chute Boxe in Brazil and had a UFC record of four wins and two defeats, with an overall MMA record of 22 wins and seven defeats.

“We have lost a warrior, friend, dedicated competitor and extraordinary human being,” Chute Boxe said in a statement.

“[He] earned the respect and admiration of all who had the privilege of knowing him,” they said on Instagram.

“Allan inspired on and off the mats with his determination, humility, respect and fighting spirit.

“Your presence will be missed immeasurable, rest in peace Allan, your name, your story and your legacy will live forever through our star.”