Historic wildfires ripping through parts of Europe have also set off dozens of World War I bombs that have been hidden for more than 100 years in Slovenia, according to a report.

A raging blaze that’s the country’s biggest since it became an independent nation has led to mass evacuations in the southwestern Kras region. Now, it’s becoming more dangerous to those trying to stop its spread.

The more than 2,000 people trying to fight it — including members of the military — have been thwarted by the dozens of hidden bombs blowing up from the heat and flames, officials told the the Slovenian Press Agency (STA).

Shrapnel from an exploded ordnance flew close firefighters, but no one was hurt in the incident.

But the added danger means that “firefighting units cannot penetrate into the fire but can only act on its edges,” Defence Minister Marjan Šarec told the agency.

“This is why the fire is being intensively fought from the air as well,” he said.

Officials stopped counting the number of explosions due to their frequency, the report said. Only explosions close to roads needed by crews were being marked, said Darko Zonjič of the national unit for the protection against unexploded ordnance.

“The temperatures at the fire site are much higher” than any time in the 104 years since World War I ended, which Zonjič said is causing the explosions.

Slovenia is just one of the European nations suffering from its worst ever wildfires as temperatures soar to deadly record highs across the continent.

Already 1,000 people have been killed in Portugal, while France, Italy and Spain are also battling blazes.