New York state has reportedly found more than 1,700 undisclosed deaths at nursing houses and adult care centers in a tally which includes people believed to have been killed by the coronavirus before their infection could be confirmed.

At least 4,813 people have died from COVID-19 at 351 of New York state's 613 nursing home since March 1, according to Governor Andrew Cuomo's administration's new count of coronavirus deaths.

The list, released on Monday, did not include vulnerable residents who were already transferred to hospitals before dying.

Nursing home residents have made up around 20 to 25 percent of the state's official tally of fatalities. Still, it is uncertain how many nursing home residents have died from the coronavirus exactly.

With the inclusion of the additional deaths, the state now lists 22 nursing homes, largely in New York City and on Long Island, as having at least 40 deaths. Sixty-two nursing homes reported between 20 and 39 deaths.

Parker Jewish Institute in Queens and the Isabella Geriatric Center in Manhattan are listed as having the most deaths: 71 and 64, respectively. Even those numbers are likely an undercount. Isabella Geriatric Center officials have said publicly that 98 residents are believed to have died, including those sent to hospitals.

Back on March 2, when only a handful of infections cases had been confirmed, the nursing homes was regarded as the most vulnerable place and the state announced to make a special effort on it. Four days later, the state directed nursing homes to screen visitors and modifying visiting hours. 

A week after that, officials suspended the visiting statewide and required temperature checks of their staffs.

But the state administration has been facing criticism over its role in monitoring and supporting New York's state-regulated nursing homes as many are struggling to treat COVID-19 patients, amass enough personal protective gear or ensure adequate staffing.

(With input from agencies)