The In-N-Out hamburger chain is sizzling mad after the city of San Francisco shut down its indoor dining for refusing to check customers' vaccination status, as is required by a local mandate.

The company's Fisherman's Wharf location — its only one in San Francisco — was temporarily shut by the Department of Public Health on October 14. Authorities said the burger chain refused to bar clients who couldn't show proof of vaccination to dine indoors, as required by a city mandate that took effect August 20.

More cities are rolling out vaccination mandates for restaurants and other businesses as the pandemic continues, including New York, New Orleans, and San Francisco. That puts the onus on restaurant owners to check patrons' vaccination status, a task that has prompted some fast food locations to simply shut their indoor seating due to staffing and safety issues, CNBC reported earlier this month.

In-N-Out ignored repeated warnings to enforce the vaccination rule, the department said, calling the mandate a matter of public health to keep COVID-19 from spreading.

"We refuse to become the vaccination police for any government," Arnie Wensinger, the chain's chief legal and business officer, said in a statement. 

In-N-Out said it considered the enforcement requirement an intrusive and offensive measure that would force it to discriminate against customers. The city of San Francisco's public health department didn't immediately return a request for comment. It tweeted about the In-N-Out Burger's closure on Tuesday.

The location has since reopened but without indoor dining.