Picture taken during a forest fire in Vichuquen, 283 km south of Santiago, on Jan 24, 2017. [Photo/VCG]

SANTIAGO - The worst wildfires in Chile's modern history are ravaging wide swaths of the country's central-south regions, as a massive Boeing 747-400 Super Tanker arrived on Wednesday on loan from the United States to help extinguish the blazes.

"We have never seen something of this size, never in Chile's history. And the truth is the (firefighting) forces are doing everything that is humanly possible and will continue to do so until the fires are contained and controlled," President Michelle Bachelet said, as she visited the hard-hit Maule region.

Forest fires are a regular feature of Chile's hot, arid summers, but a nearly decade-long drought combined with historically high temperatures have created tinder-dry conditions.

International help from France, the United States, Peru and Mexico has been pouring into Chile as the fires swept through forested hills and into neighboring towns, scorching homes, industry and the region's world-renowned vineyards. The country last week declared a state of emergency.