Florida Governor Rick Scott warned state residents that "this storm could kill you" Photo: Getty Images

Residents put plywood up in Port St Joe, Florida. Photo: GETTY IMAGES

The storm has sustained winds of 130mph (210km/h) and is due to make landfall at about midday (16:00 GMT).

More than 370,000 people in Florida have been ordered to evacuate and move to higher ground.

At least 13 people reportedly died in Central America over the weekend as a result of storm rains and floods.

Florida has declared a state of emergency, as have Alabama and Georgia.

What are the latest developments?

In its latest bulletin, the Miami-based National Hurricane Center (NHC) said Michael had become "an extremely dangerous category 4 hurricane".

It warned of a life-threatening storm surge, hurricane force winds and heavy rainfall along the north-eastern Gulf coast.

Michael, it added, could see some additional strengthening before it made landfall in the Florida Panhandle - a strip of land bordering the Gulf of Mexico - or the Big Bend area to its east.

At 02:00 local time on Wednesday, the eye of Michael was about 170 miles south-west of the coastal city of Apalachicola.

The NHC warns that some regions of Florida may experience storm surges of up to 13ft (4m).

Michael is currently moving northwards at 12mph.

On the Saffir-Simpson hurricane scale, category 4 includes winds of up to 156mph with possible severe damage to even well-built homes and trees being felled.

"Weakening is expected after landfall as Michael moves across the south-eastern United States," the NHC added.

Florida Governor Rick Scott called Michael "monstrous storm" and urged residents to listen to officials.