Firefighters have made progress in battling many of the large wildfires burning in the Southeast, but several blazes continue to creep into new areas — and investigators say more fires are being lit each day by suspected arsonists.

There are 44 uncontained large fires in the South, covering a total of more than 120,000 acres, national fire officials said Tuesday.

Arson investigations are underway in Georgia, Tennessee, North Carolina and Kentucky.

In Tennessee, 23 new fires have been reported since Friday, and 14 of them are suspected arsons, the Tennessee Department of Agriculture reported. Most of the suspected arson blazes are relatively small, the largest being a 237-acre wildfire northeast of Knoxville.

The Southern forests have caught fire amid a relentless drought. More than 47 million people are now living in drought areas, which stretch from Oklahoma and Texas all the way east to the Carolinas and parts of Virginia, according to the latest information from the National Drought Mitigation Center.

More than 5,000 people from local, state and federal agencies have been battling the wildfires across the South, authorities said. The U.S. Forest Service is investigating what caused many of the larger blazes.

The U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives has reached out to the Forest Service, offering to help investigate, Special Agent Larry Priester said. So far, he said, the agency has not joined the probe. "Their main focus now is just getting the fires contained," he said.

In North Carolina, most of the large fires burning in the western part of the state are suspected arsons, authorities have said. A $10,000 reward is being offered for information leading to the arrest and conviction of those responsible for them.

Some wildfire arsonists set fires for the thrill of it, while others are motivated by social or political causes, according to documents from the U.S. Fire Administration.

"We've had people in the past who said 'I like the lights of the fire,'" said Brian Haines, a spokesman with the North Carolina Forest Service. "People have strange reasons for starting fires."

There have been a handful of arrests in some of the smaller fires, including a man in Kentucky whose hobby was to broadcast weather reports on social media. He was charged with arson after police said he admitted to starting a wildfire to draw attention to his selfie videos on Facebook.

The fear is that whoever has started many of the large blazes might continue to set more fires.

"Based upon my primitive information on this issue, people who tend to set fires may want to do it again," North Carolina Gov. Pat McCrory told reporters at a news conference last week.