The blaze began in the Harz Mountains a day earlier, and prompted the evacuation of about 500 hikers and other tourists from the area.

About 250 firefighters were deployed on Saturday to fight the blaze, a spokesman for the district of Harz in the state of Saxony-Anhalt told AFP.

Four fire-fighting aircraft and two helicopters were helping in the effort on the Brocken mountain, according to spokesman Michael Randhahn-Schuelke.

Two more helicopters were expected to be deployed later in the day.

"The police have closed access to the area," said Randhahn-Schuelke.

Authorities at Harz National Park, which covers the affected area, said that all hiking trails around Brocken were closed.

In a message on its website, the park urged people not to enter the area "under any circumstances. Otherwise you will endanger yourself and hinder the fire brigade".

On Friday, about 150 firefighters backed by planes and helicopters had sought to quell the fire but some emergency workers were forced to retreat as the blaze spread rapidly.

A massive forest fire broke out in the Harz Mountains in September 2022. Authorities declared a state of emergency and hundreds of firefighters tackled the blaze for days.

Like other countries, Germany has been experiencing higher summer temperatures in recent years.

The EU's climate monitor on Friday said that the 2024 northern hemisphere summer saw the highest global temperatures on record, beating 2023's high and making this year likely to be Earth's hottest ever recorded.

The data from the Copernicus Climate Change Service followed a season of heatwaves around the world that scientists said were intensified by human-driven climate change.