A crew of more than 50 from all along the East Coast is working to contain a wildfire in the Great Dismal Swamp that had grown to about 3,200 acres by late Tuesday afternoon.

Firefighters are working by land and by air to build a large containment line around the fire. Once the preliminary one is built, crews will work on improving it to that the fire is unable to cross over.

“They’re not going directly up against the fire, because that’s just too dangerous,” said Barb Stewart, a public information officer for the fire response. “We’re stepping back and working on a fuel break around a much larger area. It’s moving within our big box right now.”

The fire spread less rapidly on Tuesday than on Monday, when it grew to 2,500 acres from a Sunday estimate of 200. Conditions improved a little for the firefighters on Tuesday, primarily because of less wind.

“We’ve had people coming in all day,” Stewart said. An interagency Southern Area Incident Management team has arrived to help.

The fire was first spotted Thursday evening by the personnel on board a plane traveling home from fighting wildfires in North Carolina. At that time, it was two fires — one estimated at 15 acres and another burning a single tree.

The larger fire now has engulfed the smaller blaze. The fire is burning southwest of Lake Drummond.

The blaze is threatening to grow larger than a 2008 fire in the swamp that scorched nearly 5,000 acres. It lasted for four months until a series of coastal storms finally put it out completely. It was the largest fire ever on U.S. Fish and Wildlife Service land in the Northeast region, and the longest-burning and most expensive fire in Virginia’s history. The response cost more than $12 million.

Several areas in the swamp are closed to public use activities, including scheduled tours, until further notice. Lake Drummond is closed to boating, and Railroad Ditch Road also is closed. The Lake Drummond Reservation and boat trolley, located between Lake Drummond and the Dismal Swamp Canal, are closed. The Dismal Swamp State Park in North Carolina also is closed.