Early Saturday, several vehicles were set ablaze in 13 fires set between midnight and 6 a.m., mostly in North Hollywood. Officials said they bore a resemblance to the nearly two dozen fires set in and around Hollywood a day earlier.

No one has been injured. But some residents were on edge as authorities ramped up efforts to catch the culprit or culprits on a night when resources are stretched thin as drunken New Year’s revelers hit the town.

"We’re pulling out all the stops," fire department spokesman Brian Humphrey said Saturday. "We’re hoping that the person or people responsible will be brought to swift and complete justice."

Firefighters were to be stationed around the city to respond to emergencies, while authorities set up a hotline and pored through tips. Authorities also were interviewing witnesses and sought out video footage that would offer clues, and have announced at least $35,000 in rewards for information leading to the conviction of the person or persons responsible

Among the most pressing questions: Were the fires set by a serial arsonist, multiple people or copycats? And why target cars, apparently at random?

Elyse Eisenberg, a film producer who lives in West Hollywood about a mile from a fire that was set Friday morning, said that since then she has noticed fire trucks ramping up their presence on city streets.

"I’ve seen the fire trucks stationed around town on ready alert. And that’s comforting … They’re positioned in neighborhoods ready to go like in Laurel Canyon where the Jim Morrison fire was," Eisenberg said, referring to the house of the famous late Doors singer, which was among those damaged Friday.

Active in her neighborhood association, Eisenberg says residents have been sending emails around reminding people to be on alert. She lives in a condominium building with a secure parking garage, meaning any would-be arsonist would have to get through a locked security gate, but there are open lots packed with cars nearby.

Eisenberg plans to go to a friend’s house party in Laurel Canyon for New Year’s and isn’t concerned about encountering any fires.

"I’m sure I’ll be home by then. I don’t mean to be dismissive but the fires do seem to start well after midnight," Eisenberg said.

She also revelers expected in West Hollywood will decrease the chance of an arsonist striking.

"We have an excellent police force. I’m sure they would be alert to keeping an eye out on partygoers as well as any suspicious activity," Eisenberg said.

While few clues have emerged publicly, officials have speculated that it’s plausible that one person in a car, on a motorcycle or on a bike could have set all the fires, considering the limited area the blazes broke out in.

Fire officials also have yet to set a damage figure for the blazes. In West Hollywood alone, they said flames destroyed about $350,000 worth of property.

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AP reporter Terry Tang contributed from Phoenix