A battle is under way in the Great Dismal Swamp to stop flames from consuming anymore of the national refuge.

Flames, from what officials believe was a lightning strike a week ago Monday, have already burned nearly 535 acres of the 111,000-acre swamp.

The fire is primarily along the western edge of Lake Drummond, according to Ranger Doloras Freeman. Due to the fire, trails in that area have been closed to the public. The rest of the refuge remains open, she said.

Freeman said while they believe the lightning strike occurred April 3, flames were not discovered until Friday of that week.

The fire apparently smoldered for several days before officials discovered it. The dry conditions in recent weeks and toppled trees from Hurricane Isabel several years ago have given the flames plenty of fuel.

Timothy Craig, fire management officer, Region 5, South Zone, of the U.S. Fish and Wildlife Service, said they had approximately 75 percent containment of the fire early Monday morning.

The task at hand, according to Craig, is to now stop the flames from consuming any additional acreage and let it burn out. He said he expects the fire to continue to smolder for about another week or 10 days.

“We just want to get it to the point where it won’t get any larger,” he said.

Once they have halted the firefighting portion of the operation they will monitor the area from the air for any flare-ups.

Craig said the rain on Saturday helped, but it wasn’t enough to stop the fire.

While crews on the ground were working to halt any advancement of the fire, two helicopters were using giant buckets to drop water on the flames and the hot spots. They were filling their buckets from Lake Drummond, a 3,000-acre lake in the middle of the swamp.

Firefighters from several agencies, including the Fish and Wildlife Service, Virginia Department of Forestry, were battling the fire. On Monday afternoon several trucks carrying personnel from Asheville, N.C. arrived to assist.

Craig said they are currently working 16-hour days and will scale that back once they get more containment.

The hardest part about this fire is the environment, said Craig. The swamp consists of heavy undergrowth and water in the area makes accessing the flames difficult.

Crews resorted to using Jon boats to cross a ditch and get to the burn area. At one point, a flatbed trailer was laid across the ditch to allow heavy equipment into the fire area.

Because of the location of the fire there is no threat to any structures or people.