Volkswacht Bodensee - Explosions, 'unprecedented' fire hit Berlin forest

Firefighters were unable to tackle the blaze directly due to the danger of further blasts, with emergency services setting up a 1,000-metre (3,280-foot) safety zone around the site.

Berlin fire brigade spokesman Thomas Kirstein said the situation was "under control and there was no danger for Berliners" but that the fire was expected to last for some time.

Around 250 emergency personnel were deployed to the site.

The army sent in a tank aimed at evacuating munitions at the affected storage site as well as remote-controlled de-mining robots, while drones circled the air to assess the emergency.

Water cannons were also deployed around the safety zone to prevent the fire from spreading.

Berlin mayor Franziska Giffey interrupted her holiday to visit the scene, calling the events "unprecedented in the post-war history of Berlin".

Giffey advised Berliners to close their windows but said the danger was minimal as there were no residential buildings within a two-kilometre (1.2-mile) radius and so no need to issue evacuation orders.

- Heatwave -

"It would be much more difficult if there were residential buildings nearby," she said.

Firefighters called to the site in the middle of the night were confronted with intermittent blasts that sent debris flying and hindered their work.

No one has been hurt by the fires, which came as a heatwave enveloped Germany.

Scientists say climate change is making heatwaves around the world more frequent and more intense, which increases the risk of fires.

Police said they were investigating what set off the fire.

The store holds munitions uncovered by police, but also unexploded World War II-era ordnance which is regularly dug up during construction works.

Giffey said local authorities would "have to think about how to deal with this munitions site in the future and whether such a place is the right one in Berlin".

Authorities appealed for the public to avoid the forest, popular with both locals and tourists, as several regional rail lines have been halted.

- Forest fires -

But authorities said no firefighting choppers were available as they were already in use to calm forest fires in eastern Germany.

They also said the 1,000-metre safety zone applied to the air, so there was a limit to how useful it would be to drop water on the fire from above.

The German capital is rarely hit by forest fires, even though its 29,000 hectares of forests make it one of the greenest cities in the world.

Brandenburg, the region surrounding Berlin, as well as parts of eastern Germany have for days been battling forest fires.

Heavy thunderstorms are then due to sweep into the country from the west on Friday, the German weather service said.

A cold front is predicted to bring temperatures down by more than 10C overnight in western Germany, falling to around 20-25C on Friday.

M.Ouellet--BTB