As some California counties close gun shops because of the coronavirus, even as gun dealers report a surge in customers nationwide, one state lawmaker wants Gov. Gavin Newsom to halt sales of firearms and ammunition throughout the state, except to law enforcement officers.

“Adding more firearms to our current state of affairs perpetuates the cycle of public panic and impulsive action,” Assemblyman Miguel Santiago, D-Los Angeles, said Monday in a letter to Newsom.

Santiago cited reports of sharply rising U.S. gun sales since early March and said some retailers had reported a 70% increase over an 11-day period. He also noted a report by the state attorney general’s office in January that 22,424 firearms were still owned by Californians who are legally prohibited from possessing them, despite attempts to enforce that ban.

“By suspending firearm and ammunition sales and arming Californians with strong safeguards on public health and safety reinforced by state peace officers, we can mitigate undue risks to our public,” Santiago wrote.

Asked about the request at a news conference Wednesday, Newsom said he would continue to “defer to the sheriffs and their determination of the local health” in each county.

The governor issued a statewide shelter-in-place order on March 19, telling Californians to stay at home except for essential activities. When asked at a news conference on March 25 whether he considered gun businesses to be essential, Newsom said the state would not offer any guidance and would leave the decision up to each county.

“I believe in people’s right to bear arms and I believe people are exercising that right,” Newsom said, according to published reports. “I’ll defer to sheriffs in their respective jurisdictions.”

He spoke after Los Angeles County Sheriff Alex Villanueva ordered closure of all gun stores in the state’s most populous county. After being sued by the National Rifle Association and other gun groups, Villanueva withdrew his order on March 30, saying he was persuaded by a non-binding advisory from the Trump administration’s Department of Homeland Security that gun and ammunition dealers were “essential critical infrastructure workers.”

By contrast, gun shops have been closed in most of the Bay Area. On March 31, the NRA and its allies sued Alameda, Contra Costa, Santa Clara and San Mateo counties in federal court in San Francisco for refusing to declare firearms dealers to be essential businesses. The suit claims the action violated the constitutional right to possess guns for self-defense.

San Francisco’s last gun store closed in 2015 in response to a city ordinance that required video recording of all commercial firearms sales.

Santiago’s office did not respond to a request for comment. His letter was made public by the Firearms Policy Coalition, which said his proposal for a statewide ban “would deny tens of millions of Californians their fundamental rights for an indefinite amount of time.”

Bob Egelko is a San Francisco Chronicle staff writer. Email: begelko@sfchronicle.com Twitter: @BobEgelko