More than 500 people have been evacuated in the southwestern French department of Landes as wildfires continue to spread and threaten nearby communities.

Prefect Gilles Clavreul ordered an expansion of the evacuation zone after the blaze grew to cover around 1,100 hectares, or roughly 2,700 acres, officials said on Friday. Some 525 people have now been moved to safety, up from around 400 on Thursday, when the latest fire broke out.

France is among several European countries battling wildfires amid a spell of extreme heat that has caused health emergencies and disruptions to power generation across the continent. Temperatures in Landes are expected to reach around 36°C, raising the risk of fresh flare-ups, fire chief Arnaud Fabre warned, according to French media.

Around 500 firefighters have been deployed to contain the blaze. Flames reportedly advanced to within a few hundred meters of the community of Luglon, although no homes or other property have so far been reported destroyed.

”The next fifteen hours will be decisive,” Clavreul told reporters.

Landes is heavily covered by pine forests and is particularly vulnerable to wildfires. The area burned in the current fire season has already surpassed levels recorded during the severe wildfire year of 2022. Across France, around 120,000 hectares, or nearly 300,000 acres, have reportedly burned.

The French Interior Ministry has said that 420 people were detained on suspicion of starting fires, either deliberately or through negligence.