Hurricane Irma has killed at least 22 people in the United States with at least 12 of them in Florida, and left tens of millions of people without power.

"Currently, the number of confirmed deaths attributable to Hurricane Irma stands at 12," Florida Division of Emergency Management spokesman Alberto Moscoso told AFP.

Officials said that nearly 9.5 million, just under half of Florida�s population, have no electricity, adding that it would take 10 days or more for power to be fully restored.

Florida Gov. Rick Scott said that given the sweltering temperatures, it is crucial to restore power as fast as possible.

"After visiting shelters this week and talking to people who evacuated due to Hurricane Irma, the number one thing I heard from families is that they want their power back on," Scott said.

According to CNN meteorologist Taylor Ward, "Temperatures will be around 90 for many, especially central and southern Florida for the next several days."

After wreaking havoc on Florida, Irma knocked out power in Georgia, Alabama, South Carolina and North Carolina.

Irma, which was downgraded to a tropical storm early on Monday, had ranked as one of the most powerful Atlantic hurricanes. It hit the US nearly two weeks after Hurricane Harvey made landfall in the country, claiming about 70 lives and causing property damage as it pummeled the Gulf Coasts of Texas and Louisiana with heavy rains and severe flooding.

Both hurricanes might have caused up to $200 billion in damage to Texas and Florida, similar to the costs from Hurricane Katrina that devastated New Orleans in 2005, according to an estimate from Moody�s Analytics.