YREKA, Calif. — A wildfire in the Klamath National Forest near the Oregon border was moving toward homes in two small communities and sending smoke into the Rogue Valley Tuesday.

U.S. Forest Service spokesman Mel Cagle said the fire grew by 1,000 acres overnight Monday. It had burned through more than 6.5 square miles of trees and brush 25 miles northeast of Weed.

By Tuesday afternoon, the fire was moving east toward 28 homes in the rural outposts of Kegg and Jerome, Cagle said. There were no evacuations, but the Forest Service closed a campground near Orr Lake.

Highway 97 between Weed and Klamath Falls remained open, but the Union Pacific Railroad tracks were closed through the fire area.

The 4,168-acre wildfire started Sunday. By Tuesday, it was 20 percent contained by nearly 700 firefighters and five water-dropping helicopters.

The smoke in the sky over the east end of the Rogue Valley and the western slopes of the Cascade Range Tuesday probably was from that wildfire and others burning in Northern California, said Brian Ballou, spokesman for the Oregon Department of Forestry's Southwest Oregon District.

"We don't have anything going on," he said of wildfires, noting the prevailing winds often blow smoke from the south into the valley. "The smoke lays closer to the ground in the morning and stays there until the winds start picking up."