Authorities in Puerto Rico raised the death toll from Hurricane Maria by 3 to 48 on Saturday based on a review of medical records.
The medical examiner concluded that the hurricane was the deciding factor in the three newly disclosed deaths, Secretary of Public Security Hector Pesquera said.
Precise details were not available, but one occurred in the central town of Caguas when a person was unable to get dialysis treatment after the storm knocked out power.
Another happened in nearby Juncos when a person with undisclosed respiratory problems could not get treatment.
The third occurred in the northern city of Carolina when a person suffering a heart attack was also unable to get treatment.
Pesquera said that the medical examiner is still reviewing all deaths that occurred in island hospitals around the time of the storm and the toll could rise further.
"We are reviewing each and every case to see if the storm was a direct or indirect cause," he said following a news conference in the capital. "I doubt seriously that we will have any direct at this juncture."
Maria hit the U.S. island territory Sept. 20 as a category 4 hurricane. The government says about 85 percent of the island remains without power.
Gov. Ricardo Rossello says he is pushing for outside aid to restore electricity and his goal is to have it back for half the island by Nov. 15 and for 95 percent by Dec. 31. But he conceded the task of rebuilding the transmission and distribution network is enormous.
"These are aggressive goals," Rossello told reporters.
Previously, officials had said it could take as long as March to reach that goal.