A series of explosions hampers attempts to fight the forest fire in Berlin | Germany
Repeated explosions have prevented Berlin firefighters from reaching a blaze in a forest southwest of the city that started at a police munitions site used to store World War Two bombs.
The fire started in the early hours of Thursday morning after an unexploded ordnance accidentally detonated, according to Berlin police.
The forest, in the affluent Grunewald district of the German capital, is popular with city dwellers, swimmers and dog walkers.
The fire spread in an area of approximately 1.5 hectares (3.7 acres). About 100 firefighters are on site, but were unable to get within 1,000 meters of the flames due to a series of heat-triggered explosions.
Berlin firefighters said drought conditions had already made the forest vulnerable to fires. An unprecedented number of forest fires elsewhere in Germany also means there is a shortage of firefighting helicopters to tackle the blaze.
The police site is used to store unexploded ordnance, ranging from confiscated illegal fireworks to World War II munitions that are regularly discovered at construction sites across the city.
Controlled explosions are periodically carried out by experts on site to safely dispose of stockpile, but no detonation has occurred since June due to dry conditions, resulting in more explosives being stored than habit.
The fire also shut down a section of the overhead S-Bahn railway, disrupting public transport across the city and disrupting long-distance trains to Amsterdam, and shut down the Avus motorway.
The nearest residential building was nearly 2 miles away and area residents were urged via cell phone warnings and radio broadcasts to close windows and doors and turn off air conditioning units. Clouds of thick gray smoke dominated the horizon and the sounds of explosions were heard for several miles. No injuries were reported.
Police and firefighters were using drones and helicopters to assess the progress of the fire and were taking containment measures to stop its spread, including watering the edge of the forest. A spokesperson said three separate fires had been identified.
The intensity of the heat was holding back forces, he said, adding that it was necessary to bring in new firefighters frequently due to heat exhaustion. Reinforcements were called in from other parts of Germany.
Jan Thomsen, from the Berlin environment department, said the lack of rain meant the fire could take hold quickly.
He said the forests were very dry and had “not been able to recover due to the long periods of drought”. Asked by reporters whether it was a good idea to have an explosives site in a forest, he said: “We will have to deal with these security issues once the cause of the fire has been determined”.