US President Joe Biden has postponed planned visits to Germany and Angola later this week as Hurricane Milton approaches the state of Florida.

"I just don't think I can be out of the country at this time," he said at the White House on Tuesday.

Biden said Milton, which is already one of the most powerful storms to ever form in the Gulf of Mexico and was on Tuesday upgraded back to Category 5, "could be the worst storm to hit Florida in over a century."

He said he was working "to increase the size and presence" of the federal government's response.

Canceling his foreign trips, he urged Floridians to "evacuate now" and head inland, saying it was "a matter of life and death."

He also called on airlines and hotels not to engage in "price gouging" by massively upping their rates.

"Kamala and I are keeping all of you in our prayers," Biden said, referring to Vice President and 2024 Democratic presidential candidate Kamala Harris.

Despite being downgraded to a Category 4 hurricane by the National Hurricane Center earlier on Tuesday, forecasters warned Milton still posed "an extremely serious threat to Florida." The storm has since been recategorized back to level 5.

When will Hurricane Milton make landfall?

The storm is expected to make landfall in the populous Tampa Bay area in western Florida on Thursday morning local time, with sea level surges of up to 20 feet (6 meters) expected along coastal areas where evacuation orders have been put in place.

The region is already reeling from the devastation caused by Hurricane Helene with warnings that debris from that storm could be picked up and hurled like "missiles" by the 145 mph (230 km/h) winds.

Late on Sunday, Florida Governor Ron DeSantis declared a state of emergency for 51 of the state's 67 counties, saying that Milton could have "major, major impacts."

"You do not have to evacuate hundreds of miles away; you can evacuate tens of miles, you do have options," DeSantis said at a Tuesday morning news briefing, assuring residents there would be enough gas to fuel their cars for the trip.

"You do not have to get on the interstate and go far away."

Deanne Criswell, administrator of the Federal Emergency Management Agency, added: "I need people to listen to their local officials to get out of harm's way. People don't need to move far. They just need to move inland."

"Helene was a wake-up call, this is literally catastrophic," Tampa Mayor Jane Castor said on CNN.

"I can say this without any dramatization whatsoever: If you choose to stay in one of those evacuation areas, you are going to die."

Biden cancels Germany trip

President Biden had been expected to arrive in Berlin on Thursday evening for a meeting with German Chancellor Olaf Scholz and President Frank-Walter Steinmeier.

He had then been scheduled to travel to the western state of Rhineland-Palatinate to host a Ukraine summit at the US Ramstein airbase.

Scholz said the meeting would be rescheduled.

"It would have been a very important meeting and we prepared it on all sides," Scholz said in an interview with German broadcaster RTL.

"But I have to say, quite frankly, that if such storms were raging in my country, then I would also make this decision," he added. 

"If such storms were raging in my country, I would make the same decision," he said in an interview with broadcaster RTL

mf/wmr (dpa, AP)