The National Hurricane Center said, in its latest advisory, that Irma, now a Category 2 storm with maximum sustained winds of 110 mph, is about 5 miles north of Naples, Florida.
Police officers have been assigned to check the other 42 assisted living facilities in the area "as a precautionary measure", Sanchez added.
In a separate statement, the Florida Department of Health's Mara Gambineri wrote "this facility is located across the street from one of Florida's largest hospitals, which never lost power and had fully operating facilities".
Conservative MP James Duddridge, who was a Foreign Office minister with responsibility for the Caribbean and British Overseas Territories, said: "It is absolutely essential we change these rules. This facility was not listed as a top critical infrastructure, top-tier critical infrastructure facility, and that's what we work with the counties, for them to help identify those facilities", said Gould.
Miami-Dade County Mayor Carlos Gimenez said officials were providing ice to 27 senior residence facilities still without power, local media reported.
Patients were treated for dehydration, breathing difficulties and other heat-related ills, authorities said. About 2.6 million utility customers still were without power in the state Thursday morning, officials said.
Irma hit Florida about two weeks after Hurricane Harvey pounded Houston, killing about 60 people and causing some US$180 billion in damage, mostly from flooding.
Aerial footage showed patients sitting outside in wheelchairs and others being taken out of the facility on stretchers.
"The devastation left by Hurricane Irma was far greater, at least in certain locations, than anyone thought - but wonderful people working hard!"
Police have launched a criminal investigation.
A third call later came in as well, police said.
The nursing home was bought at a bankruptcy auction two years ago after its previous owner went to prison for Medicare fraud, according to news reports at the time of the sale.
The Florida Health Care Association also released a statement calling the situation "a profound tragedy".
Irma has also been blamed for the death of four people in SC and two in Georgia.
The White House did not specify which area of the state the President would tour during his stop, but sources told CNN he would travel to the Fort Myers area, on Florida's gulf coast.
At least six people appeared to die of carbon monoxide poisoning from generators in Florida, the AP news agency reported. Hollywood Fire Chief Christopher Pratt said it was "more than likely" that heat played a factor in the residents' conditions.