A major fire that broke out at Warner Bros. Studios Leavesden has been extinguished, authorities said Thursday.

The fire was first reported late Wednesday on a sound stage not in use. At least 18 fire trucks were called out to fight the blaze, and firefighters spent 15 hours tackling it. No injuries have been reported.

It is still not clear what caused the blaze.

The studio, located in Hertfordshire, just outside London, is the home of the Harry Potter films and the Harry Potter studio tour, which was unaffected. Productions shooting at Leavesden – including Armando Ianucci’s space comedy, “Avenue 5,” for HBO – were also uninterrupted.

“The fire at Warner Bros. Studios is now out, but several vehicles remain on site,” local authorities said. Some roads that had been closed to assist the fire services have been reopened, but other roads remain closed.

Fire and rescue services were first called to reports of a fire about 11:30 p.m. Wednesday, and battled it through the night. Reinforcements arrived at the scene the following morning. One local road was closed in order for firefighters to run a hose from a nearby canal.

Numerous big films including “Mission Impossible” and “James Bond” have used Leavesden, but it remains best known as the home of the Harry Potter franchise.