ALBANY, N.Y. — New York Gov. Andrew Cuomo's administration confirmed Thursday that thousands more nursing home residents died of COVID-19 than the state's official tallies had previously acknowledged, dealing a potential blow to his image as a pandemic hero.

The surprise development, after months of the state refusing to divulge its true numbers, showed that at least 12,743 long-term care residents died of the virus as of Jan. 19, far greater than the official tally of 8,505 on that day, cementing New York's toll as one of the highest in the nation.

Those numbers are consistent with a report released just hours earlier by Attorney General Letitia James charging that the nursing home death count could be off by about 50%, largely because New York is one of the only states to count just those who died on facility grounds, not those who later died in the hospital.

"While we cannot bring back the individuals we lost to this crisis, this report seeks to offer transparency that the public deserves," James said in a statement.

The 76-page report from a fellow Democratic official undercut Cuomo's frequent argument that the criticism of his handling of the virus in nursing homes was part of a political "blame game," and it was a vindication for thousands of families who believed their loved ones were being omitted from counts to advance the governor's image as a pandemic hero.

"It's important to me that my mom was counted," said Vivian Zayas, whose 78-year-old mother died in April after contracting COVID-19 at a nursing home in West Islip, New York. "Families like mine knew these numbers were not correct."

Cuomo's office referred all questions to the state health department. Several hours after the report, State Department of Health Commissioner Howard Zucker released a lengthy statement attempting to refute James' report but which essentially confirmed its central finding.

Zucker's figure of 12,743 nursing home resident deaths included for the first time 3,829 confirmed COVID-19 fatalities of those residents who had been transported to hospitals. 

Those figures could be even higher, but the health department said its audit was ongoing, didn't break out deaths presumed but not confirmed to be caused by the virus, and omitted those in assisted living or other types of long-term care facilities.

Zucker, however, still took issue with James' characterization of his department's official tally as an "undercount." He said "DOH was always clear that the data on its website pertains to in-facility fatalities."

James has for months been examining discrepancies between the number of deaths being reported by the state's Department of Health, and the number of deaths reported by the homes themselves.

Her investigators looked at a sample of 62 of the state's roughly 600 nursing homes. They reported 1,914 deaths of residents from COVID-19, while the state Department of Health logged only 1,229 deaths at those same facilities. 

Thursday's release backed up the findings of an Associated Press investigation  last year that concluded that the state could be understating deaths by as much as 65%. 

State Sen. Gustavo Rivera, a Democrat who has blasted the Cuomo administration for its incomplete death count, said he was "sadly unsurprised" by the report.

"Families who lost loved ones deserve honest answers," Rivera said. "For their sake, I hope that this report will help us unveil the truth and put policies in place to prevent such tragedies in the future."

Cuomo, who last fall released a book touting his leadership in dealing with the virus, has not been shy about using New York's lower nursing home death count to make the argument that his state is doing better than others in caring for those in such facilities. 

"There's also no doubt that we're in this hyper-political environment so everybody wants to point fingers," Cuomo told CBS "This Morning" in October. "New York, actually, we're number 46 out of 50 in terms of percentage of deaths in nursing homes … it's not a predominantly New York problem."

The attorney general's report also took aim at New York's controversial March 25 policy that sought to create more space in hospitals by releasing recovering COVID-19 patients into nursing homes, which critics contended was a driving factor in causing nursing home outbreaks. 

James' report said those admissions "may have contributed to increased risk of nursing home resident infection and subsequent fatalities," noting that at least 4,000 nursing home residents with COVID-19 died after that guidance. But James' report said the issue would require further study to conclusively prove such a link.

New York's health department released a much-criticized report last summer that claimed the March 25 policy, which was reversed in May, was "not a significant factor" in deaths.

James' review also found that a lack of infection controls at nursing homes put residents at increased risk of harm, that homes with lower federal scores for staffing had higher fatality rates, and that a broad measure Cuomo signed in April shielding nursing homes and other health care providers from lawsuits may have actually encouraged homes to hold back on hiring and training.

"As the pandemic and our investigations continue," she wrote, "it is imperative that we understand why the residents of nursing homes in New York unnecessarily suffered at such an alarming rate."