Crews have responded to two small fires near Flagstaff in recent days.
Coconino National Forest officials say forward progress was stopped Tuesday morning on the four-acre Sinclair Fire west of Fort Tuthill County Park.
The Chisholm Fire also broke out around midnight Tuesday on forest service land near the Flagstaff Pulliam Airport.
The agency says several fires have been reported in the area lately and investigating the pattern is a top priority.