Another California city has gone on the offensive against “ghost guns.”

San Diego Mayor Todd Gloria signed an ordinance on Thursday banning the possession and sale of “ghost guns.” The rule, entitled Eliminate Non-serialized Untraceable Firearm (ENUF), defines the items as unfinished frames and receivers and non-serialized firearms.

“San Diego has seen a dramatic increase in gun violence across our city using ghost guns,” Mayor Gloria said in a press release. “These guns are untraceable and can end up in the hands of people prohibited from having firearms making them a threat to public safety. Addressing the proliferation of ghost guns aligns with my commitment to have San Diego lead on gun violence prevention.”

The new ordinance comes when other major California cities have made a push to ban “ghost guns.” Both San Francisco and Los Angeles have taken similar steps in recent months.

It also comes as unfinished gun parts have become the center of the national debate over guns. President Joe Biden (D.) is pushing to unilaterally expand the ATF’s power to regulate unfinished frames and receivers by redefining what constitutes a firearm through federal rulemaking. His proposal received nearly 300,000 public comments, the majority of which were against the idea.

Proponents of “ghost gun” bans argue criminals use homemade firearms to skirt gun laws. Opponents argue home gun building is a tradition older than even the country itself and has never been illegal.

City Councilmember Marni von Wilpert, who authored the ordinance, praised the mayor for “standing with me to protect our communities from gun violence.” The mayor’s press release claimed the rule was necessary due to increased police seizures of ghost guns over the last couple of years.

“In 2020, San Diego saw a 169% increase in the number of ghost guns retrieved and impounded compared to the previous year,” the release said. “This year, San Diego has already surpassed the number of ghost guns impounded in all of 2019 and 2020, with the expected number of ghost guns recovered by the San Diego Police Department (SDPD) to double by the end of this year.”

It also claimed that the majority of seized ghost guns were from individuals who could not legally own a firearm.

“The vast majority of ghost guns recovered by SDPD are seized from people who cannot pass state or federal background checks because of a criminal conviction involving a felony, violent misdemeanor, and from persons who are prohibited due to mental illness,” the release said.

The ordinance will go into effect on October 23.