A rash of arson fires in Los Angeles that has seen more than 30 cars torched in recent days had authorities on the lookout for at least one suspect on Saturday, amid fears more blazes could result in serious injury.

So far, no residents have been wounded but one firefighter was treated and released for injuries fighting the spate of apparently related arson fires, which triggered a broad local and federal response, authorities said.

At some locations, blazes have spread from torched cars to carports and homes.

One of the fires damaged a house in the Hollywood Hills, where Doors lead singer Jim Morrison was inspired to write the 1968 song Love Street about the place and his girlfriend, Pam Courson.

Los Angeles police stepped up patrols, and the city fire department planned to maintain a command post for the New Year's weekend in an area where many of the blazes have occurred.

Arson investigators have been called in to review video footage, map where and when the fires were set and interview witnesses.

Investigators were trying to determine if the string of fires was set by one person or more than one person, said Officer Norma Eisenman, a police department spokeswoman.

But police said they were looking for a man driving a 1990s Lexus ES300.

At least 11 vehicles were burned on Saturday in the San Fernando Valley suburb of Los Angeles, police said. The city fire department reported vehicle or structure fires at other locations.

The early Saturday fires followed on 21 intentionally set fires involving vehicles or car ports in the Hollywood area late on Thursday and early Friday morning, according to the fire department.

With fires having spread to structures, the fire department provided a conservative estimate for $350,000 in property damage for the blazes on Thursday and Friday alone.

Authorities were offering rewards totaling $60,000 for information that leads to the arrest and conviction of the arsonist, the fire department said.

We are dead serious about trying to apprehend the individual or individuals who are responsible for this, Los Angeles County Supervisor Zev Yaroslavsky told reporters on Friday. We want to get these S-O-Bs before they hurt somebody.

No suspects were in custody Saturday, Eisenman said. Police released people who had been detained in the investigation after determining they had no connection to the fires, she said.

Investigators were going over numerous tips from residents and surveillance recordings from area apartment buildings, Eisenman said.

The investigation includes the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives, the Los Angeles County Sheriff, Los Angeles County Fire Department and Beverly Hills Fire Department.