Authorities say a wildfire that destroyed nearly 30 homes in central Washington state was likely human-caused.

A Chelan County sheriff's spokesman said Wednesday that investigators have ruled out any natural causes, such as lightning. But they're still looking into whether the fire was set on purpose or by accident.

Officials say the blaze that started Sunday scorched about 4 ½ square miles in the city of Wenatchee, located about 150 miles west of Seattle. They said 29 homes were destroyed and four business complexes in the commercial area were damaged.

Wenatchee Mayor Frank Kuntz also announced he's signing a declaration to ban fireworks within the city limits through July 4.

County commissioners have declared the county a hazardous fire area, which prohibits outdoor burning and the use of fireworks.