Hurricane Maria, who hit Puerto Rico in September last year, has claimed 4645 lives, instead of 64, according to US authorities, according to a study by Harvard University.
The scientists who attended the university from 3299 randomly selected families who survived the hurricane were asked to report their known deaths from Hurricane Maria.
They then extrapolated data obtained throughout the island and compared it to its annual mortality rate.
The mortality rate for the period from 20 September to 31 December 2017, 14 cases per 1000 people, while the figure in the previous year was 62% lower.
Although Harvard experts admit the figures are not accurate, they say deaths are 10 times higher than official figures revealed by government agencies.
Local and federal authorities did not provide the necessary medical care and could not provide timely electricity during and after the cyclone.
As a result, one-third of the deaths occurred due to lack of medical care, late and inappropriately, the authors believe.
In addition, scientists have noted that island authorities refuse to publish regular reports of deaths.
The New York Times reported earlier that Hurricane Maria could have killed more than 1000 people.
The paper reached this conclusion by comparing daily mortality statistics with a period of 40 days after the disaster.