The new figures appeared in a July draft destined for the U.S. Congress and include fatalities indirectly connected to Hurricane Maria.

Puerto Rico has been investigating the initial death toll from Hurricane Maria and believes at least 1,400 people died as a result of the storm, rather than the previously reported 64, the New York Times reported Thursday.

The new figures appeared in a July draft destined for the U.S. Congress, entitled 'Transformation and Innovation in the Wake of Devastation.' The documents extended the list of victims to include those killed in the aftermath of the September storm, making it "much larger" than initially reported.

Following the storm, the death toll in the U.S. territory surged to the highest figure recorded in four years. A survey conducted in November of over 100 funeral homes on the island showed that at least 499 deaths were indirectly caused by Hurricane Maria.

Additional power failures and lack of medical and food supplies contributed anywhere from 800 to 8,500 additional fatalities, a Harvard study estimates.

Puerto Rican State Spokesman Pedro Cerame said George Washington University is researching the case and the state will eventually announce a "realistic calculation."

"We do not want to say it out loud or advertise it as an official number... until we see the study and have the accuracy," Cerame said.

In an interview with CNN, the executive director of the Federal Affairs Administration of Puerto Rico, Carlos Mercader, said: "We did not commission the study to prove there were 64 (deaths). We wanted a scientific and epidemiological study that would give us light, not only on the number; we know that the number is higher, but also the reasons why it happened."

According to the Harvard study, released in May, some 4,600 people died due to Hurricane Maria. Still, the official fatality report has maintained that only 64 people were killed when the storm hit the island on September 20.