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The number of reported coronavirus deaths in long-term care facilities has more than doubled to 5,670 since last week, according to state health data gathered by NBC News, driven by huge increases in hard-hit states like New York, where more than 2 percent of nursing home residents have died of the virus.

The death count is based on data from 29 state health departments and includes nursing homes, assisted living and other long-term care facilities. An NBC News investigation published last week found 2,246 deaths associated with long-term care facilities in 24 states.

There are now 3,466 long-term care facilities in 39 states with known coronavirus infections, according to state data – nearly 1,000 more facilities than state officials reported to NBC News last week.

For more on this story, watch NBC's "Nightly News with Lester Holt" tonight at 6:30 p.m. ET/5:30 p.m. CT.

The federal government does not track nursing home residents who have died from the virus, or the numbers of facilities that have had outbreaks, despite the high mortality rate among those who are elderly and have underlying health conditions. Some high-population states like Florida have refused to disclose such information and access to testing is highly limited in many states, which means the actual number of COVID-19 deaths in long-term care facilities is likely significantly higher.

By far the largest increase in nursing home deaths was in New York state, where the death count soared from 1,330 last week to 3,060, as of Wednesday, according to a state health spokeswoman. That means that 2.3 percent of the estimated 131,000 New York residents who live in nursing homes and assisted living facilities have died from the coronavirus so far.

In New Jersey, the coronavirus has spread to more than 95 percent of the state’s 375 long-term care facilities, according to state health officials. Within the last eight days, the number of nursing homes deaths has risen nearly five-fold in New Jersey, from 128 to 625 deaths, state health officials said.

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Massachusetts has also been hit hard, with 444 nursing home deaths in 214 facilities. The state did not provide data on the number of deaths when NBC News conducted its first tally last Friday.

Despite the rapid and deadly spread of the virus, just 17 states have disclosed the names of nursing homes with known coronavirus infections, according to NBC News' latest count. Eight of these states have identified the affected facilities in lists posted publicly online.

Not every state included in the NBC News tally provided updated data this week.

Some families with loved ones in nursing homes hit with outbreaks have told NBC News that they fear they are being kept in the dark about the expanding number of cases in the facilities where their family members reside. The federal government only requires that nursing homes inform the family members of an infected resident, not other families.

Niki Smith previously told NBC News she only learned of a coronavirus outbreak of more than 100 cases in her father’s Nashville nursing home when her brother discovered the news on Facebook.

“I wish I could count on their communication,” Smith said. “I am going to the news for information rather than the facility.”

Seema Verma, the administrator for the Centers for Medicare and Medicaid Services, which oversees nursing homes, said on a Wednesday conference call with reporters that the agency was “looking to go further” to require that nursing homes publicly disclose cases. But Verma stopped short of announcing any policy changes for long-term care facilities.

The federal government has faced sharp criticism from Democratic senators and advocates for nursing home residents for failing to track the number of facilities with coronavirus outbreaks and the number of deaths.

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Verma conceded the federal government could do more. “We recognize there should be more reporting,” Verma told reporters. She said the agency would disclose plans to track nursing home outbreaks later this week that would provide “real time information about COVID in nursing homes.”

Two leading associations for nursing homes nationwide said over the weekend that they support more data collection and full disclosure of cases.

Katie Smith Sloan, president and CEO of Leading Age, the association of nonprofit providers of aging services, told NBC News in a statement that the group encourages data collection by the government to track the virus’s spread. “It is crucial that all providers be transparent" and extend "communication about positive cases with staff, residents and families,” Sloan added.

Others in the industry have also encouraged nursing homes to be more open about coronavirus outbreaks in their facilities.

“Notify all residents, families and staff when the facility has its first confirmed COVID-19 case,” Mark Parkinson, president and CEO of the American Health Care Association and the National Center for Assisted Living said in a statement to NBC News.