File Photo/BLM

BOISE, Idaho (AP) — A dozen aircraft and more than 130 firefighters are working to contain three central Idaho wildfires sparked by lightning before they become so large they'll be impossible to put out until the end of the fire season.

Boise National Forest officials on Wednesday say a 20-acre fire about 3 miles from Idaho City is the most concerning because it's in heavy timber and about a mile from a phone tower.

Spokesman David Seesholtz says a 66-acre fire near Pilot Peak is less worrisome because it's moved to the top of a ridge. A third fire northwest of Prairie and south of Arrowrock Reservoir has burned about 150 acres in steep country but is also in an old wildfire from 1992.