HOUSTON, Feb. 12 (Xinhua) -- A large wildfire broke out on Sunday in the U.S. state of Oklahoma, burning hundreds of acres and forcing hundreds of people to evacuate their homes.

The wildfire occurred in southeast Oklahoma City, capital city of the Oklahoma state, and the cause of the fire remains unclear, according to the Daily Oklahoman.

The flames encroached on several mobile homes and a salvage yard containing vehicles and tires in the area.

Helicopters from the Army National Guard were trying hard to contain the wildfire by airdropping water while firefighters were working together with the Oklahoma Forestry Services on the ground.

The fire has burned about 877 acres so far and hundreds of people have been evacuated as a precaution.

Oklahoma is under a national fire advisory through Feb. 14 because of the high risk of wildfires.