Firefighters battling the Waldo Canyon wildfire west of Colorado Springs in late June uncovered a marijuana grow in the national forest that had a living area, dams and irrigation lines.

The announcement Tuesday by the U.S. Attorney's Office says 7,500 marijuana plants with an estimated $15 million street value were found on the 22-acre site.

Authorities did not immediately say whether charges were filed.

Some of the plants had been destroyed by the fire that killed two people and destroyed 350 homes in Colorado Springs. The rest were removed by U.S. Forest Service law enforcement.

U.S. Attorney John Walsh says he and other US attorneys in other states are targeting illegal marijuana grows on public land.

Since 2009, 16 illegal marijuana grows have been raided on public lands in Colorado.