efe-epaSan Francisco, USA

Rescue workers were searching for more than 100 people who were missing on Sunday due to devastating forest fires in California that have left at least 31 dead.

According to information provided by the Butte County Fire Department, the so-called "Camp Fire", which has killed at least 29 people and left three firefighters injured, has razed close to 45,000 hectares (111,197 acres), 6,450 homes and 260 commercial structures.

The Butte County Sheriff's Office said that the last six bodies were recovered from the town of Paradise.

The Camp Fire, with 25 percent containment, has almost completely devastated the town, which was home to 26,000 residents.

An air quality alert has been in place in San Francisco, approximately 280 kilometers (174 miles) away, since the fire broke out on Thursday.

The Camp Fire is one of the deadliest in the history of the state.

Foresic scientists have been deployed to the scene to try to identify the bodies recovered.

Authorities were still investigating the cause of the fire.

In addition to the Camp Fire, another major blaze was searing through southern California, where two people have died, according to local police.

The "Woolsey Fire", which was only 10 percent contained, has burned 33,600 hectares in an area that includes the celebrity enclaves of Malibu, Calabasas and Thousand Oaks.

Apprixamtely 250,000 people state-wide have been forced to flee their homes.

Donald Trump has blamed California's forestry authorities for the scale of the damages caused by the fires, and threatened to withhold federal aid.

"There is no reason for these massive, deadly and costly forest fires in California except that forest mismanagement is so poor. Billions of dollars are given each year, with so many lives lost, all because of gross mismanagement of the forests", Trump wrote on Twitter.

"Remedy now, or no more Fed payments!", the president warned.

He later praised the efforts of emergency workers and firefighters, and urged residents in communities threatened by the blaze to listen and respond to evacuation orders.

Trump had approved emergency funding for the state on Friday.