New York (AFP) - New York City will require all municipal workers to get vaccinated against coronavirus or take a weekly test, Mayor Bill de Blasio said Monday as the Delta variant fuels an uptick in cases in the metropolis.

The order will go into effect from September 13 and will apply to more than 300,000 city personnel, including police officers, fire fighters and teachers.

"This is about our recovery. This is about keeping people safe," de Blasio told a press conference.

The move comes after the mayor announced last week that the city's 30,000 public hospital workers would need to get vaccinated or face weekly testing from August 2.

The measure announced Monday is the most stringent measure taken so far in the US megacity to boost vaccination rates following a campaign based on voluntary participation and incentives.

In New York, 59 percent of the entire population has received at least one dose of a vaccine against Covid-19 but the speed of injections has slowed.

Controversy is building in the United States over what steps should be taken to increase vaccination rates against the Delta variant, which accounts for more than 89 percent of US infections, according to estimates.

Many health officials are pushing to make vaccination mandatory, at least for certain segments of the population.

On Monday, 57 medical groups representing millions of doctors, nurses, pharmacists and other health workers called for mandatory vaccinations for all health staff.

"The health and safety of US workers, families, communities, and the nation depends on it," said the statement, whose signatories included the American Medical Association and the American Nurses Association.

Several Republican-led states have instead passed laws banning coercive measures, though, particularly in schools.

The September 13 date will coincide with the return of one million students to New York's public schools for the new academic year.