LOS ANGELES - An arsonist set numerous vehicle fires early Friday that spread to nearby houses and apartment buildings in Hollywood and neighbouring West Hollywood, including a home once occupied by Doors frontman Jim Morrison.

The four-hour onslaught started shortly after midnight and sent firefighters scrambling to douse the flames. In nearly every case, the fire started in a parked car.

Dozens of people were rousted from their homes, power was disrupted in several neighbourhoods and Los Angeles police were put on tactical alert in the Hollywood area. One city firefighter was treated and released from a hospital after a fall while battling one blaze. No other injuries have been reported.

"It was a long, tough night," said Los Angeles County fire Battalion Chief Tom Sullivan.

Arson investigators from the police and sheriff's departments said there was no suspect description and they were looking for building security videos and witnesses.

"If you see something, say something," Sullivan told a press conference.

One of the homes damaged by the arson fires was in Laurel Canyon where Morrison and his girlfriend once lived, neighbours said.

Sandy Gendel, who owns a nearby restaurant, said he heard explosions from what he later believed were car tires. He saw flames 30 feet (9 metres) high coming from the deck of the former Morrison house and a gutted Mazda Miata.

"It was just like a towering inferno," Gendel said.

Jeff Dorman, who lives in the neighbourhood, said he and his wife were awakened by noise in the street.

As he and his neighbours watched the firefight, he said they worried about embers floating toward their houses because they are so close together. They also were concerned about a firebug being loose in their neighbourhood.

"One spark could have been a huge problem," Dorman said. "The fire department did a fantastic job."

Unless authorities catch the arsonist, they are preparing for possibly another round of fires. City Councilman Tom LaBonge said all agencies involved were going to meet for a strategy session.

"These are not trash can fires on street corners. We are just a second away from tragedy," he said.

LaBonge said the arsonist is targeting underground parking in mid-century type apartments that have no security gates and putting some kind of incendiary device under cars.

All of the fires were in a four square mile (10 square kilometre) area, he said.

It was the second day of arson fires in the area.

Two people were arrested Thursday following a spate of similar car and rubbish fires. Those men remained in custody Friday, officials said.

Hollywood is served by the Los Angeles city police and fire departments. Adjacent West Hollywood is a separately incorporated city served by the Los Angeles County fire and sheriff's departments.