Catastrophic wildfires continue to ravage California, as one blaze nearly doubled in size over the last three days, making it the largest in the US state's history, according to authorities.

One Maoist was gunned down and two policemen received injuries in a gunfight on Friday at Basaguda village in Chhattisgarh's Bijapur district, police said.

A major fire broke out in a cold storage near a crowded North Delhi industrial area on Wednesday, a Fire Services official said.

California firefighters and emergency services continued trying to contain about a dozen fires still active in the state which have devastated over 100,000 hectares, according to official data.

The toll in the 17 wildfires that were currently blazing in California has increased to eight, according to authorities.

At least six people have died in a deadly fire that has ravaged a large swathe of California and continues to grow amid dry weather conditions severely hampering efforts to control the blaze.

A mother and her five children were killed on Saturday as a fire swept through a motel in the US state of Michigan.

US President Donald Trump declared on Saturday a state of emergency in California and ordered the federal government to provide additional assistance due to the wildfires that since July 23 have devastated the region and forced authorities to evacuate close to 38,000 people.

A raging wildfire in California has killed two firefighters and prompted 38,000 evacuations, destroying scores of homes and threatening other dwellings and businesses.

The death toll in the wildfire which swept through a once idyllic seaside resort in eastern Attica rose to 87 on Friday, according to the latest update from local authorities.