Hurricane Ian has caused unprecedented damage after trapping people in flooded homes and leaving more than two million without power, says Florida’s governor.

Ron DeSantis called the damage “historic” and disaster officials believe thousands could be displaced in the long term.

US President Joe Biden has declared a major disaster, releasing federal funds to pay for measures such as temporary housing for displaced people.

Ian was a category four storm with winds up to 150mph when it struck southwest Florida on Wednesday, making it the joint fifth-strongest hurricane to hit America.

Lee County sheriff Carmine Marceno told US media that deaths could be “in the hundreds” and that he’d received thousands of 911 calls.

“It crushed us,” Sheriff Marceno said. “We still cannot access many of the people that are in need.”

But Florida’s governor said the remark was speculation based on the deluge of 911 calls and that he hoped many of those people would have stayed safe.

Mr DeSantis said there were so far two unconfirmed fatalities possibly related to the storm.

One is believed to be a 72-year-old man killed near Daytona Beach after going outside to drain his swimming pool during the storm.

Electricity remained cut for 2.6 million in Florida early on Thursday morning, according to website Power Outage US.

There was virtually no mobile phone service in some areas and internet connectivity was also affected.

“Portable towers are on the way for cell service. Chances are your loved ones do not have the ability to contact you,” said the Collier County sheriff’s office.

“We can tell you as daylight reveals the aftermath, it’s going to be a hard day.”

300 trucks of food and water heading out

A “severe and threatening” storm surge as high as 10ft, including “destructive waves”, was ongoing on the southwest coast from Englewood to Bonita Beach, according to the National Hurricane Center.

Similar warnings telling people to “seek higher ground now” were in place on other sections of the Florida coast.

In Port Charlotte, about 65 miles south of Tampa, the surge flooded a hospital emergency room and ripped off part of the intensive care unit’s roof.

“We’ve never seen a flood event like this,” said Florida’s governor at a media conference on Thursday morning.

“We’ve never seen storm surge of this magnitude – and it hit an area where there’s a lot of people… It’s going to end up doing extensive damage to a lot of people’s homes.”

Mr DeSantis said bridges were being inspected for safety, but that the causeway to Sanibel island was impassable after a chunk fell into the sea and cut off more than 6,000 people.

More than 300 trucks containing food and water are also being sent to southwest Florida, said officials, who warned the storm remained a major threat to the state.

Thousands of people could be displaced in the long term due to the “catastrophic” damage, Deanne Criswell, head of the Federal Emergency Management Agency, told CNN.

Ian was downgraded to a tropical storm early on Thursday but was forecast to return to near-hurricane strength later, ahead of a second predicted landfall in South Carolina on Friday.

On its way to the US, Ian hit Cuba and cut off power to nearly all the island’s 11 million people.