PAYSON, AZ - The 3,100-acre Poco Fire continues to grow on the Tonto National Forest.
490 firefighters are battling the blaze which was first reported Thursday afternoon.
Fire crews say their main focus is to protect the power lines nearby.
Weather and terrain remain a concern; firefighters are working on steep slopes and in hot conditions.
Officials said Sunday the fire is 15% contained.
No structures are threatened by the blaze, which is burning about 6 miles north of the town of Young in steep and rugged terrain.
The fire's cause still is under investigation.