It is being reported that a fire engulfed a dormitory at Flamengo's youth team training centre, Ninho do Urubu, while players were sleeping, killing 10 people and injuring three.
None of the victims have been identified as of yet, but players aged between 14 and 17 are known to have used the dormitory of the Brazilian club.
The fire took place at 05:10 (07:10 GMT) and was extinguished by 07:30, according to BBC.
It is believed that those wounded were taken to the Lourenço Jorge hospital in Barra da Tijuca.
It is not yet known if any players were hurt in the blaze but Firefighter Douglas Henaut confirmed that the area is accommodation for youngsters who play for the club.
"The kids from the Flamengo youth team were sleeping there at the time," the firefighter Douglas Henaut told Globo News.
Former Flamengo player Vinicius Junior, who joined Real Madrid in the summer, reacted to the tragic news on social media earlier today.
A number of Brazilian clubs have also expressed their solidarity.
"What sad news! Let us pray for all! Strength, strength and strength." he said.
More to follow...