Crews were trying to contain a wildfire Monday in northern Arizona that has closed the Tuzigoot National Monument and its surrounding trails.

Coconino National Forest officials say the fire was spotted Sunday night and has charred an estimated 100 acres of marsh and grassland by Monday afternoon with no containment yet.

They said the Tuzigoot observatory lookout area has already been burned through but the fire hadn’t burned any building or structures.

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Some 100 firefighters and other personnel were working on the wind-driven fire. There’ was no immediate word on the cause of the fire.

Tuzigoot National Monument is northwest of Cottonwood and east of Clarkdale.