Military helicopters backed by tractors on the ground hauled water Sunday to help firefighters tame Belgium’s largest modern-day wildfire, which mushroomed in size since breaking out two days earlier in a hard-to-access nature reserve.

Local farmers have poured in to help battle the blaze in the High Fens park near the German border, an area of fragile peatlands and pine forests popular with hikers, joining several hundred firefighters and emergency workers.

Near the blaze’s edge in Baelen, a ballet of tractors were pulling in tankers of water drawn from Robertville lake a few miles north – with water-bearing Chinook helicopters flown in from the Netherlands to spearhead the effort.

“Right now there are about 15 tractors queuing to fill up,” Jean-Pierre Robert, who manages a lakeside hotel, told AFP.

“We moved our cows, and opened up all our fences to give them access,” said the 54-year-old.

Authorities described the conditions Sunday as still “challenging”, but two of the fire fronts — heading towards the localities of Jalhay and Monschau — were now “under control”, according to Interior Minister Bernard Quintin.

From 80 hectares burned on Friday, the day the fire started for reasons still unknown, the area affected jumped to 850 hectares Saturday morning — and by early Sunday had spread to 3,000 hectares.

The blaze broke out in an area that was ravaged by massive fires in 1911, during a similar period of heatwaves and drought — and is the country’s largest wildfire since then.

The entire area has been blanketed by a thick plume of yellowish smoke, prompting the partial evacuation of two villages close by.

Around 20 people spent the night in a local sports hall, the Liege governor’s office said, with others believed to have found shelter with friends and family — or in some cases ignored evacuation orders to stay home.

Fumes have travelled into the neighbouring Namur province, where authorities had to ask residents to stop saturating emergency phone lines with reports of the smell.

The governor’s office said shifting winds had complicated firefighters’ efforts but that “the defensive line protecting evacuated areas is holding”.

“No homes have been affected at this stage, although the fire remains close and smoke levels are significant,” it said.

Help from the skies

Firefighters from across Belgium and from Germany have been deployed to assist, supported by next-generation fire engines.

But authorities said operations were “particularly complex” because of the fens’ terrain – a patchwork of heath, peat bogs and raised wooden boardwalks where heavy vehicles risk sinking into the ground, and firefighters struggle to tackle the fire at close range.

They were counting heavily on aerial assistance to bring the situation under control.

European Commissioner Hadja Lahbib told AFP Sunday that two water-bombing aircraft had arrived from Sweden, backing up four helicopters — two Belgian and two Dutch — already on site.

A liaison officer was tasked with coordinating the aerial resources “to prevent accidents,” she said.

Prime Minister Bart De Wever has thanked Belgium’s European partners for the assistance Like much of Europe, Belgium has experienced a new spell of intense heat and drought in recent days.

Temperatures reached as high as 37C in some parts of the country on Friday, creating conditions conducive to wildfire outbreaks.

But rescue teams have been unable to access the area where the High Fens fire first broke out, meaning its precise cause remains unknown.