The blaze swept through a building at Brazil's biggest football club's complex in Rio de Janeiro, killing six players and four team staff.
Fire swept through a training facility for Brazil's most popular football club Flamengo Friday, killing at least 10 people, authorities said.
The pre-dawn blaze in Rio de Janeiro hit a building that housed youth-category players aged 14 to 17, firefighters said.
In addition to the deaths, three people were injured in the fire.
The dead were six players and four team staff, Brazilian channel Sportv said.
The team said in a Twitter post that is was in mourning. Flamengo
The cause was not immediately known.
Globo TV broadcast aerial footage of the fire, which it said had been brought under control after it burned for two hours.
The fire broke out at 5 am in the Vargem Grande district of Rio in a modern facility where the top-flight professional Flamengo squad also trains, the news website G1 said.
Só de lembrar as noites e dias que passei no ct, é de arrepiar. Ainda sem acreditar, mas em oração por todos! Que Deus abençoe a família de cada um! 😢 pic.twitter.com/RcBsdH3GME— Vinicius Jr ⚡️ (@vini11Oficial) February 8, 2019
The main team had been due to practice at the same facility later in the morning.
Youth league teams also train at the facility, known as Ninho do Urubu.
Flamengo is the most popular club in football-crazed Brazil.
Distraught relatives rushed to the facility seeking information about loved ones, TV footage showed.
Uma tristeza muito grande, meus pêsames e sinceros sentimentos a todos familiares e a nação rubro-negra. Terrível tragédia!!! pic.twitter.com/ociPSpWvVd— Ronaldinho Gaúcho (@10Ronaldinho) February 8, 2019
Football players and clubs have been sharing messages of solidarity on Twitter.
The club has turned out names like Ronaldinho, Zico, Julio Cesar and Bebeto.
The training camp is in an area of western Rio that was hit by a huge storm Wednesday night. Six people were killed.
Because of those heavy rains, the football facility remained without electricity or water Friday as the fire broke out, G1 reported.