KARACHI, Pakistan 

Japan's worst wildfires in more than three decades raged unabated as firefighters backed by military helicopters continued to struggle to contain the blazes, which are burning thousands of hectares of land every day, local media reported Monday.

Firefighters have been battling the fires in the forest around the northeastern city of Ofunato since last Wednesday, public broadcaster NHK reported.

The multiple blazes have so far burned around 2,100 hectares. Over the past 24 hours, another 3,000 hectares has been burned.

Backed by helicopters of Japan's Self-Defense Forces, firefighters are battling the blazes from the air and the ground as smoke blows towards residential areas.

At least one person has been killed while more than 80 buildings have been damaged.

"We are concerned about the spread of the fires. We believe in the power of firefighting from the air and the ground. We'll try to put out the blazes," Ofunato Mayor Fuchigami Kiyoshi was quoted as saying.

Nearly 1,200 residents have already taken shelter in facilities.