NEW YORK- New York City will require proof of vaccination for indoor activities including restaurants, gyms and performances, Mayor Bill de Blasio said on Tuesday.

The announcement is the latest in a string of initiatives aimed at encouraging more residents to get vaccinated as the Delta variant spreads in the nation's most populous city.

"We know this is what's going to turn the tide," de Blasio told a news conference.

(Reporting by Maria Caspani, Editing by Frank McGurty) ((maria.caspani@thomsonreuters.com; + 1 646 223 4074 ;))