Fire authorities contained a blaze at the velodrome in Rio de Janeiro’s Olympic Park on Wednesday, April 8.

The Rio De Janeiro Fire Department said the brigade was deployed early on Wednesday to fight a large fire on the roof of the building, in an operation that included 85 firefighters from 13 units, and more than 25 vehicles.

“Rapid response was crucial to containing the fire, which was confined to the structure’s exterior. The internal space, including the Olympic Museum, has been preserved,” the brigade said.

The velodrome was built for the 2016 Rio Olympics, and is Brazil’s largest and most prominent track cycling center. Rio de Janeiro Mayor Eduardo Cavaliere told journalists the cause of the fire was under investigation.

“The blaze did not compromise the structure nor cause major damage to the interior of the stadium. We will rebuild the cover so the velodrome can reopen to the public as soon as possible,” Cavaliere said.

Two similar blazes occurred in 2017, both caused by falling paper sky lanterns, according to reports.