Images from Portugal show aftermath of deadly wildfire that killed 61

— -- Images are coming out of Portugal of the aftermath of a fire that scorched a forested area in the center of the country over the weekend, leaving at least 61 dead, according to a spokesperson at Portugal's interior ministry.

Of the victims, 59 people were killed from flames or smoke inhalation and two more were killed in a road accident trying to flee the blaze, according the spokesperson Aicha El Hammar.

The number of dead, which includes at least four children, is expected to rise, El Hammar said. A spokesperson for Portugal's interior ministry tells ABC News that this is the deadliest forest fire in Portugal's history.

A bolt of lightning that struck a tree in the Pedrógão Grande area may be responsible for sparking one major fire, investigators told The Associated Press.

Portugal's Prime Minister Antonio Costa said that there had been 156 fires across the country over the weekend, with 11 still active -- and two blazes that are "particularly problematic."

One of multiple fires that spread in Portugal this weekend sent flames sweeping across a road, which reached motorists who became trapped in their cars. That blaze led to the bulk of the damage and fatalities, Costa told the media on Sunday. Costa said everyone who died was on one road or next to it.

Forty-seven bodies were discovered in or adjacent to their cars, El Hammar told ABC News.

"This tragic situation took place in only one of the fires, particularly at a road next to it," Costa told the media. "I don't want to talk yet about the cause of the fire because we are facing the greatest tragedy of human lives so, what we must do now is to calmly provide all the resources to fight the fires."

Costa also took to Twitter to thank rescue workers for their efforts to control the blaze, and send condolences to the victims who died.

"This is a region that has had fires because of its forests, but we cannot remember a tragedy of these proportions," Valdemar Alves, mayor of Pedrógão Grande, told the AP. "I am completely stunned by the number of deaths."

The Iberian peninsula is currently sweltering under a severe heatwave, with temperatures exceeding 104 degrees in some regions.

On Sunday, Pope Francis led thousands of people in silent prayer for the victims of what he called the “devastating fire,” while the Portuguese football team offered its “deepest sympathies to the families, friends and loved ones of the victims of the fires."

The Associated Press and ABC News’ Molly Hunter and Ben Gittleson contributed to this report.