With auto break-ins on the rise, San Francisco supervisors on Tuesday introduced new legislation intended to step up enforcement efforts and approved two ordinances seeking to reduce thefts from rental cars.

The board's actions come at a time when the city's problems with auto burglaries have been made painfully clear by two recent gun thefts from law enforcement officers who left their weapons in parked cars.

One of those guns, stolen from a San Francisco police officer last month, was used just days later in a fatal shooting in the city's Mission District. The other gun, a duty weapon stolen Sunday from the trunk of a rental car where it had been left by a sheriff's deputy, has not yet been located.

The thefts are part of a growing problem. Police reported earlier this month that auto burglaries were up by 28 percent citywide for the period from January to July this year compared to last year, with the Mission

District seeing the largest jump of 182 percent.

In response, Supervisors Norman Yee and Hillary Ronen introduced legislation Tuesday calling for the police department to devote at least one officer at each station to property crimes such as auto break-ins and bicycle thefts.

Yee introduced similar legislation last year, only to have it vetoed by Mayor Ed Lee.

Ronen said she approached Yee about reviving the legislation after learning of the recent gun thefts. She said her constituents often tell her their cars get broken into several times a year, and that they often do not bother to report the incidents to police.

"Needing to fix a three or four hundred dollar window on a regular basis is devastating to many families that are barely hanging on in San Francisco as it is," Ronen said, noting that the expense almost served as a sort of "tax" on residents.

Yee described the law enforcement gun thefts as "infuriating."

"Despite assurances that all efforts were being made to address the growing issue of car break-ins, home break-ins and bike thefts, the problem has only gotten worse," Yee said. "We cannot stand idly by as policy makers hoping this problem will go away."

The board also unanimously approved two pieces of legislation Tuesday focused on rental cars, which are reportedly targeted by thieves who know tourists are less likely to report theft and more likely to carry valuables on their person.

Legislation from Yee would prohibit rental car companies from placing visible barcodes and advertisements on vehicles that can mark them clearly as rentals.

Another piece of legislation by Board President London Breed would require rental car companies to warn customers about car burglaries and advise them to remove valuables and lock their car doors.

Breed said the city had found that just adding signage in the Alamo Square area warning people about auto burglaries had helped to reduce the number of break-ins in the area.

"When people come to San Francisco and rent a car, we don't want them to go away with these terrible experiences," Breed said. "If we make sure folks know what is going on, it won't stop the car break-ins but it's a step to reducing them."