What used to be the U.S. epicentre of COVID-19 has now reached a promising milestone.

"For the first time in months, we have a 24-hour period where no one in this city died from the coronavirus," Mayor Bill de Blasio said Monday.

"Let's have many more days like that."

The test positivity rate in New York City is now at 2%.

But that doesn't mean the battle against the virus is over. De Blasio pointed to rising infection rates among young adults ages 20 to 29, which he called "worrisome."

The mayor said the city will be "doubling down" on trying to quash the virus among young adults by offering more mobile testing vans, outreach programs and mask giveaways.

De Blasio said the city has set up 10 new testing sites in the Bronx, Queens and Brooklyn.