Forest fires in southern Chile, fueled by intense heat and strong winds, advanced further Tuesday after destroying nearly 40,000 hectares (100,000 acres), officials said.

President Sebastian Pinera blamed the La Nina weather phenomenon and "global warming" for the lack of rain.

"We still have 20 fires that are active," Pinera told reporters, warning that Chile is facing "an extraordinarily risky and vulnerable" fire season due to dry summer weather.

Interior Minister Rodrigo Hinzpeter said some of the fires might have been set intentionally.

"The probability that they were caused intentionally, unfortunately, is not a probability that we can dismiss," Hinzpeter said.

The worst of the blazes were concentrated in Chile's Bio Bio region, about 500 kilometers (300 miles) south of Santiago, where about 22,500 hectares have been destroyed, according to Office of National Emergencies (ONEMI).

About 500 people have been evacuated from the area and 162 homes destroyed. A 75-year-old man died early Sunday when he refused to leave his home.

The damage prompted the authorities to declare the region a "disaster zone," which will give residents access to federal emergency assistance.

Bio Bio governor Victor Lobos said it was suspicious that eight of Arauco Forest fires started simultaneously Friday morning in different places.

Juan Carlos Munoz, the mayor of the town of Cauquenes, said that some 200 families had been affected by the fire and that 30 homes had been destroyed.

The first of the fires began six days ago in the Torres del Paine National Park.

An Israeli citizen, Rotem Young Singer, 23, was arrested Saturday on suspicion of starting the fire.

He faces a possible penalty of up to 60 days in jail and a $300 fine.

Singer denies wrongdoing.