New York City will require all of its municipal workers — including teachers and police officers — to get coronavirus vaccines by mid-September or face weekly COVID-19 testing, Mayor Bill de Blasio announced Monday.

The rule is expected to affect about 340,000 city employees, making the city one of the largest employers in the U.S. to take such action.

While it isn’t a vaccine mandate — no workers will be forced to take a shot — officials hope the inconvenience and discomfort of weekly tests will persuade many to overcome a reluctance to get inoculated.

“This is about our recovery. This is about what we need to do to bring back New York City,” de Blasio said. “This is about keeping people safe.”

But some of the unions representing city workers balked at the announcement, saying the city couldn’t impose the requirement without negotiations.

“New York City is a union town, and that cannot be ignored,” said Henry Garrido, executive director of District Council 37 of AFSCME. DC 37 represents about 100,000 New York City employees across several departments.

Hours after de Blasio’s announcement, officials in California announced that state employees and all health care workers will be required to show proof of COVID-19 vaccination or get tested weekly.

New York Gov. Andrew Cuomo declined to answer a question about whether he will require state employees to be vaccinated. Speaking at a news conference at Yankee Stadium, Cuomo urged localities to consider vaccinating public-facing government workers.

The Sept. 13 deadline in New York City coincides with the start of public school, when the Democratic mayor has said he expects all pupils to be in classrooms full time. City health care workers and employees in congregate setting such as group homes will face earlier deadlines.

The move comes as the city battles a rise in COVID-19 cases fueled by the highly contagious delta variant. Since the end of June, the daily average of new cases has increased by more than 300%.

Last week, the city had announced it was mandating vaccinations or weekly testing for workers in the city’s hospital system.

De Blasio expanded the requirement Monday and urged private employers to adopt similar rules.

“My message to the private sector is: Go as far as you can go right now,” the mayor said. “I would strongly urge a vaccination mandate whenever possible, or as close to it as possible.”

City workers’ unions offered mixed responses to the new mandate.

“Vaccination and testing have helped keep schools among the safest places in the city,” the United Federation of Teachers said in a statement. “This approach puts the emphasis on vaccination but still allows for personal choice and provides additional safeguards through regular testing.”

But the union that represents the city’s 4,300 EMS workers blasted the city for not consulting them.

“The city and the mayor cannot simply disregard the civil liberties of the workforce,” said FDNY EMS Local 2507 President Oren Barzilay.

He said some EMS workers — like some other people around the country — are concerned about taking a vaccine that got fast-track, emergency use authorization but not yet a full approval from federal regulators.

The three vaccines authorized in the U.S. still underwent the normal massive testing required of any vaccine. The U.S. Food and Drug Administration’s acting commissioner, Dr. Janet Woodcock, told a Senate committee this week that the agency “did not cut any corners” on safety.

City workers who choose testing will be responsible for getting it done. Tests are available to city workers and the general public at city-run sites, private walk-in clinics and many other locales for free to the person being tested; insurers or public money covers the cost.

Asked about union objections, de Blasio said the city has a right to require that its workforce gets vaccinated or tested.

“When it comes to the health and safety of our workers in the midst of a global pandemic, we have the right, as employers, to take urgent action to protect people’s health, to protect their lives,” he said.

The number of vaccine doses being given out daily in the city has dropped to less than 18,000, down from a peak of more than 100,000 in early April. About 65% of adults in the city are fully vaccinated.

Meanwhile, caseloads have been rising for weeks, and health officials say the variant makes up about seven in 10 new cases.

De Blasio has said that he does not plan to reimpose a broad indoor mask mandate, as Los Angeles County has done. Masks are required in some settings such as public transportation.

De Blasio said unvaccinated city employees will be required to wear masks indoors at all times.

Asked how the city would handle unvaccinated employees who don’t want to wear masks in the workplace, city labor relations commissioner Renee Campion said, “If employees refuse to comply, they just can’t be at work. And in fact, they will not be paid.”