New York City, already a world epicenter of the coronavirus outbreak, sharply increased its death toll by more than 3,700 victims on Tuesday, after officials said they were now including people who had never tested positive for the virus but were presumed to have died of it.

The new figures, released by the city’s Health Department, drove up the number of people killed in New York City to more than 10,000, and appeared to increase the overall United States death count by 17 percent to more than 26,000.

The numbers brought into clearer focus the staggering toll the virus has already taken on the largest city in the United States, where deserted streets are haunted by the near-constant howl of ambulance sirens. Far more people have died in New York City, on a per-capita basis, than in Italy — the hardest-hit country in Europe.