Chilean President Gabriel Boric has declared a state of catastrophe in two regions where deadly wildfires have left at least 18 people dead.

More than 50,000 people have also been evacuated in the Ñuble and Biobío regions, about 500km (300 miles) south of the capital Santiago.

Boric said the death toll was expected to increase.

The most dangerous fire has swept through dry forests bordering the coastal city of Concepción. About 250 homes have been destroyed, disaster officials said.

Local media have shown pictures of charred cars in the streets.

Chile's forestry agency, Conaf, said firefighters were battling 24 fires across the country on Sunday. The most threatening, it added, were in Ñuble and Biobío.

The fires have burnt through 8,500 hectares (21,000 acres) in the two regions so far.

"In light of the serious ongoing wildfires, I have decided to declare a state of catastrophe" in the two regions, Boric said in a post on X.

"All resources are available," he added.

Under a state of catastrophe, Chile's armed forces can be deployed to help.

The bulk of the evacuations were carried out in the cities of Penco and Lirquen, just north of Concepción, which have a combined population of 60,000.

Strong winds have fanned the flames, exacerbated by high summer temperatures, endangering communities and hampering firefighting efforts.

Much of Chile is under heat alerts, with temperatures expected to reach 38C between Santiago and Biobío in the coming days.

Chile has experienced a series of devastating fires in recent years, worsened by long-term drought.

Two years ago, forest fires killed at least 120 people in the Valparaíso region near Santiago.