Firefighters prepare to fight flames caused by wildfires in Puren, Chile on Saturday.

Video. Watch: Chile's emergency services battle deadly forest fires

The death toll in forest fires raging through southern Chile has risen overnight to 23, officials said on Saturday.

The death toll in forest fires raging through southern Chile has risen overnight to 23, officials said on Saturday.

Eleven of the deaths were in the town of Santa Juana, in Concepcion province.

The fires, sparked by a devastating heatwave, have threatened several rural towns, destroying at least 88 homes and sweeping through 47,000 hectares of forest.

The National Disaster Prevention and Response Service said at least 24 people have been injured so far, and that out of 251 active fires, 80 of them were out of control.

Chile earlier declared a state of disaster in several central-southern areas including the Nuble and Biobio regions - allowing extra resources to be rushed to the area - but fires have also affected the Maule and La Araucania regions.

Watch the video above.