BERLIN (REUTERS) - A forested area almost the size of three football pitches was on fire in western Berlin on Thursday (Aug 4) after a blaze broke out at a bomb disposal site during a city-wide heatwave.

The fire service said that the blaze had spread across 15,000 square metres in the German capital’s Grunewald, a vast woodland area home to upscale villas, popular swimming lakes and the sealed-off ammunitions dump.

Emergency services reported a number of explosions in the area, where a 1,000-metre radius has been blocked off.

A spokesperson for the fire service said no residential areas were affected.

The bomb disposal site in Grunewald, a secured area, is used to defuse old ordnance, as well as weapons and fireworks, the spokesperson added.

Berlin frequently carries out bomb disposal operations due to ordnance still being discovered from World War Two.

The blaze and resulting explosions have prompted authorities to restrict road and rail transport in and around the Grunewald forest, with trains connecting Berlin to the nearby city of Potsdam cancelled.

“Do not enter the woodland,” the fire service warned in a tweet.

Earlier on Thursday, smoke could be seen billowing in the distance over sailing boats at the German capital’s Lake Wannsee.

Berlin is facing a weather warning currently. The German weather service DWD forecast one of the hottest days of the year yet with temperatures on Thursday expected to reach between 34 and 38 degrees Celsius.