Police investigating a fire at a Berlin mosque on Monday night said they had ruled out arson as a potential cause.
Officers found no evidence of a deliberate attack and no traces of a break-in, a police spokesman said on Tuesday afternoon.
More than 60 firefighters were called to the scene of a burning construction site at the Mevlana Mosque on Monday night.
No one was at the site when the fire broke out and no one was injured.
"As we got to the scene, the fire looked massive," a fire department spokesman said at a press conference on Tuesday morning.
The fire started in the back courtyard where construction materials were being stored. Investigators say the flames started in the wooden palletes and moved to the front of the building.
"The flames jumped onto the foil covering the window sites and then licked the facade of the building," he said.
Investigators are still looking into how the fire started. Police had originally suspected the fire was started deliberately.
The inside of the building was badly damaged by the smoke.
The Mevlana Mosque has been undergoing a series of renovations and extensions since 2013.
The Mevlana parish has 350 members and is a founding member of the Islamic Federation of Berlin.