Some 800 emergency workers were battling a forest fire in Germany's Saxon Switzerland National Park on Monday with little improvement in sight.
"The fire is in a controllable area, but flames are still coming out of the ground," dpa news agency quoted Thomas Kunz of the district administration office as saying.
"The high temperatures around 30 degrees Celsius make the number (of workers) necessary because it is a very intensive physical operation," Kunz said.
The dry and hard ground has to be dug up with hoes and spades to fight the pockets of embers, he said.
As things stand, the operation will continue at this level until at least the end of the week.
The use of so-called circular sprinklers, which irrigate a larger area and suppress the flames, has been effective, but these can only be set up in clearings.
Due to the strong sunlight, the water evaporates quickly and may not penetrate deep enough into the soil layers, Kunz said.
According to the German Weather Service, no rain is expected for the entire coming week.
Separately, fire fighters in Berlin were still attempting to extinguish a blaze in the capital's Grunewald forest, which broke out four days ago due to an explosion at a nearby police blasting site.