Fire swept through a training facility for Brazil’s most popular football club Flamengo Friday, killing at least 10 people and injuring three others, news outlets said.

The pre-dawn blaze in Rio de Janeiro hit a building that housed youth-category players aged 14 to 17, TV Globo said. It broadcast aerial footage of the fire, which it said had been brought under control.

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.

That main team had been due to practice at the facility later in the morning.

Flamengo is Brazil’s most popular club in the football-crazed nation.