Belgium is battling its largest wildfire on record which has burned around 2,700 hectares (6,700 acres) in the eastern High Fens nature reserve near the German border.
The fire has approached to within 3 kilometers (2 miles) of the German border, causing authorities in Germany to warn of smoke danger.
On Saturday, the European Union deployed three helicopters and two water bombers as Belgium deployed additional firefighters in a bid to bring the massive blaze under control.
Authorities ordered around 600 residents in parts of Waimes, Sourbrodt and Buetgenbach to evacuate as shifting winds and heavy smoke raised concerns that the fire could reach homes. Tourists were also advised to leave the area.
"You can't see a thing anymore, there's smoke everywhere," David Rodolfs, a restaurant owner in Waimes, told the AFP news agency.
A gymnasium in a neighboring municipality was opened up to offer shelter.
How have firefighting efforts fared?
The blaze, which broke out on Friday, has spread rapidly across peatlands and pine forests. Belgian Interior Minister Bernard Quintin told AFP he was "shocked" at the fire's speed and extent of the destruction.
"There is a risk that the fire could reach homes, but we are deploying all available resources to protect them," Nicolas Yernaux, a spokesperson for the regional authorities in Wallonia, said.
Difficult terrain has hampered firefighting efforts, with operations relying heavily on aerial resources and forcing firefighters to allow difficult-to-access areas to burn, according to Yernaux.
Meanwhile, Belgium activated the EU's civil protection mechanism, bringing in three helicopters and two water-bombing aircraft from the Czech Republic, Sweden and the Netherlands.
Firefighters from Germany and Luxembourg have also joined the response, while farmers have helped emergency crews by wetting down the area.
Residents in Germany's Monschau warned of possible evacuation
Authorities in the German town of Monschau in the Eifel region, which is located just 2 kilometers from the border, have warned residents to prepare for possible evacuation.
They also warned of health dangers from smoke and have advised people living in three districts of the town to temporarily seek accommodation elsewhere if possible.
However, the local fire brigade has said it does not expect the fire to enter German territory any time soon.
"We are continuing to monitor the situation," Philipp Krüger, the operations manager of the Monschau fire brigade, told the DPA news agency.
Monschau, a major tourist attraction in the Eifel region, has some 12,000 residents. It is particularly known for its picturesque Old Town with its half-timbered houses.
It is located just some 23 km from the site of another major blaze in Germany's Eifel region that forced some 2,000 people from their homes on Thursday.
Climate change making wildfires spread faster
Belgium has experienced another spell of extreme heat this week, with temperatures reaching 37 degrees Celsius (98.6 Fahrenheit) in parts of the country.
Scientists say human-caused climate change is increasing the likelihood of hot and dry conditions that allow wildfires to spread faster and burn longer.
European Commissioner Hadja Lahbib called the blaze the latest sign of the "climate upheaval" affecting the continent.
"Never before has the wildfire season started so early in the year and reached such northern latitudes," she said.
