The governor's top aide, Melissa DeRosa, confirmed the contents of the recording of a September conference call with Democratic state legislators, first reported by the New York Post, in which she admits that the governor's office withheld the numbers due to concerns they would "be used against us" by the Justice Department under then-President Donald Trump.
The figures were ultimately revealed last month as part of an investigation into COVID-19 nursing home deaths by the office of New York Attorney General Tish James.
Sources tell ABC News that Albany lawmakers will begin discussing whether to strip Cuomo of some his coronavirus emergency powers in the aftermath of the revelation. It’s unclear whether the leaders of either the Assembly or the Senate would be on board with such a move.
"He starts tweeting that we killed everyone in nursing homes," DeRosa said of Trump on the conference call recording, a transcript of which was provided by DeRosa to ABC News. "He starts going after [New Jersey Gov. Phil] Murphy, starts going after [California Gov. Gavin] Newsom, starts going after [Michigan Gov.] Gretchen Whitmer. He directs the Department of Justice to do an investigation into us."
"And basically, we froze, because then we were in a position where we weren't sure if what [numbers] we were going to give to the Department of Justice or what we give to you guys ... was going to be used against us," DeRosa told the legislators. "We weren't sure if there was going to be an investigation."
In a statement released Friday, DeRosa said, "I was explaining that when we received the DOJ inquiry we needed to temporarily set aside the Legislature's request to deal with the federal request first."
"We informed the Houses of this at the time," her statement said. "We were comprehensive and transparent in our responses to the DOJ and then had to immediately focus our resources on the second wave and vaccine rollout."
Republicans immediately seized on the admission by an aide to the Democratic governor, who was speaking on the call to fellow Democrats who hold the Senate majority.
"Governor Cuomo and his administration must be investigated from top to bottom and he must be stripped of his emergency powers," New York Senate Minority Leader Rob Ortt said on Twitter.
The spokesperson for Assembly Speaker Carl Heastie confirmed that Cuomo's office asked for more time last year in compiling nursing home data after an August request.
The report released last month on the results of the state attorney general's investigation concluded that a larger number of nursing home residents died from COVID-19 than the New York State Department of Health's published nursing home data reflected, due in part to many nursing home deaths being counted as hospital deaths. The number of nursing home residents who died from COVID-19 may have been undercounted by as much as 50%, the report said.
The probe also found that a directive from Cuomo based on guidance from the state Department of Health to admit COVID-19 patients into nursing homes in the early days of the pandemic "may have put residents at increased risk of harm."
In March, as cases surged, Cuomo issued an order that required nursing homes to accept COVID-19 patients being discharged from hospitals, as long as they were "medically stable," in order to help free up hospital beds for the sickest patients. Under the policy, nursing homes receiving the patients were barred from testing the patients to see if they might still be contagious.
After facing criticism from nursing home advocates, the governor in May amended the March order, prohibiting hospitals from discharging patients to nursing homes unless they tested negative for COVID-19.
ABC News' Laura Romero contributed to this report.