New Year's Eve revelers are reminded that firing a gun in celebration is a felony, Los Angeles officials warned Tuesday.

"Let's not place others in harm's way by shooting a firearm in the air," Mayor Antonio Villaraigosa said at a news conference where he was joined by sheriff's and police officials. "It is not only illegal. It is just plain stupid."

Last year, the Los Angeles County Sheriff's Department saw a 19% increase in the number of reports of shots fired during the New Year's festivities, while the LAPD reported a 10% jump. The increases came after nearly a decade of declines in such incidents.

LAPD Asst. Chief Michel Moore said last year's uptick is a warning that the community needs to do more to stem the problem.

"We need your help in identifying the few individuals who...engage in this activity," Moore said. "If you see or hear shots being fired, immediately call 911."

He warned anyone hoping to shoot a weapon to celebrate to think twice.

"You will be arrested. You will go to jail...this is state prison time," he said. "It is disastrous for the innocent victims and it will be disastrous for your future."

Sheriff Lee Baca said that in some areas his deputies would be aided by a so-called ShotSpotter system, which uses noise sensors to quickly track the location of gunfire.

"It is accurate within 10 feet," Baca said. "We will have that gunshot before a phone call can be made."-- Richard Winton