New York Gov. Andrew Cuomo said Monday he is asking private businesses such as bars and restaurants to require proof of vaccination against Covid-19 as a condition for admission.

The number of daily Covid cases in New York has increased “four-fold” to more than 2,000 cases over the past month as the highly contagious delta variant spreads, Cuomo said during a news conference. Data shows fully vaccinated individuals are less likely to catch, get infected with the virus or suffer from severe disease, he said.

“I am asking them, and suggesting to them, go to vaccine-only admission,” he told reporters, referring to private businesses. “I believe it is in your best interest.”

Infectious disease experts and public health officials fear Covid cases — fueled by the delta variant — could continue to surge into the fall season, when Americans head back indoors and employers begin to bring workers back to the office.

In an attempt to slow the spread of the virus, some businesses are asking customers and their employees to show proof of vaccination. On Friday, Disney said it is requiring all salaried and non-union hourly employees in the U.S. to be fully vaccinated against Covid by the end of September.

Radio City Music Hall “did this months ago,” Cuomo said Monday. “Reopened. Vaccine only. Sold out all of the shows.”

Cuomo’s comments came the same day he announced a vaccine mandate for employees of the state’s MTA and Port Authority, giving transportation workers the option to get vaccinated by Labor Day or face weekly coronavirus testing. The mandate is similar to an order Cuomo issued for state hospital employees last week in response to the surging delta variant.