Wildfires that have killed 20 people in southern Chile and wiped out entire towns raged for a third day Monday, fanned by warm temperatures and strong winds at the height of the southern hemisphere summer.

The blazes started Saturday in the Nuble and Biobio regions -- about 500 kilometers (310 miles) south of the capital Santiago -- and have since ripped through an area the size of the US city of Detroit.

Around 1,000 homes have been destroyed or damaged, officials said.

President Gabriel Boric said Monday that firefighters had managed to contain some of the blazes but that others remained "very active" and that new fires had broken out in the Araucania region bordering Biobio.

Both Nuble and Biobio were declared disaster areas, allowing for the deployment of soldiers who patrolled a desolate landscape of melted cars, twisted metal and houses reduced to rubble.

"It was horrible. I tried to wet the house as much as possible, but I saw the flames coming toward my neighborhood. I grabbed my son, my brother got my dog out, and we fled," Yagora Vasquez, a resident of the small port town of Lirquen, which was particularly hard hit, told AFP.

Residents returned to what remained of their homes on Monday, digging through the rubble and ash to salvage what they could.

Vasquez told AFP she had chosen to live in Lirquen -- on a hill far from the sea -- after seeing the devastation wrought by the tsunami of 2010 that killed more than 500 people in the same region of Chile.

This time the threat came from the forest.

- `A wave of fire` -

Mareli Torres similarly moved away from the coast after the tsunami, only for her home to be destroyed this weekend in "a wave of fire, not water."

"This is much worse, much more devastating. In the earthquake the sea surged, there was destruction, but compared to this it`s nothing," said Torres, 53.

Of the two-story house she lived in with her family for nearly two decades, only blackened walls and a haze of smoke remained.

More than 3,500 firefighters were fighting the fires in Nuble and Biobio on Monday.

Temperatures in the area hit around 25C (77F) on Monday, slightly lower than at the weekend.

Wildfires have severely impacted south-central Chile in recent years, especially in its warmest and driest months of January and February.

A 2024 study led by researchers at the Santiago-based Center for Climate and Resilience Research, found climate change had "conditioned the occurrence of extreme fire seasons in south-central Chile" by contributing to a long-term drying and warming trend.

In February 2024, several fires broke out simultaneously near the city of Vina del Mar, northwest of Santiago, resulting in 138 deaths, according to the public prosecutor`s office.

Unprecedently large areas of the country burnt during the 2016-17 and 2022-23 fire seasons.

Elsewhere in southern South America, wildfires have burnt more than 15,000 hectares in recent days in Argentine Patagonia.