The death toll from powerful storm Helene jumped to at least 93 on Sunday, with one county in North Carolina alone reporting 30 deaths, authorities said, as rescuers battled to reach people in need across the southeastern United States.

The storm left a swathe of damage across several states, some of them key battlegrounds in the November presidential election, prompting Donald Trump to announce a visit to a hard-hit area on Monday -- a clear bid for political capital.

High winds and torrential rain pummeled towns and cities across Florida, Georgia, North Carolina, South Carolina and Tennessee. Homes were destroyed, roads flooded out and power cut off to millions.

"We're hearing (of) significant infrastructure damage to water systems, communication, roads, critical transportation routes, as well as several homes that have been just destroyed by this," the administrator of the Federal Emergency Management Agency, Deanne Criswell, said Sunday.

At least 93 people were killed in the extreme weather -- 37 in North Carolina, 25 in South Carolina, 17 in Georgia, 11 in Florida, two in Tennessee and one in Virginia, according to tallies from local authorities compiled by AFP.

"We have another devastating update. We now have 30 confirmed losses due to the storm," Quentin Miller, the sheriff in North Carolina's Buncombe County, which includes the tourist city of Asheville, told a briefing.

Flash flood warnings remained in effect in parts of western North Carolina, National Weather Service director Ken Graham said, adding that they were due to the risk of dam failures.

The weather was expected to ease in the affected areas by around Tuesday, he said.

Nearly 2.3 million households remained without power on Sunday, according to tracker poweroutage.us.

US Department of Energy official Matt Targuagno said that crews were working hard to restore electricity but warned it would be "a complex, multi-day response."

Thousands of people continued to seek assistance in shelters run by the American Red Cross, organization official Jennifer Pipa said.

- Bridges washed away -

Helene blew into Florida's northern Gulf shore as a huge Category Four hurricane with winds of 140 miles (225 kilometers) per hour.

Even as it weakened, it wreaked havoc.

US President Joe Biden said Sunday that one of his senior advisors was in Florida monitoring the situation.

North Carolina saw some of the worst of the flooding, with Governor Roy Cooper saying rescuers were being forced to airlift supplies in some areas due to damaged or flooded roads.

"I don't know that anybody could be fully prepared for the amount of flooding and landslides that they are experiencing right now," Criswell said on CBS, adding that more search and rescue teams were being deployed.

William Ray, director of the state's emergency management department, warned that conditions were still extremely dangerous.

Hundreds of roads across the region remained closed, with several bridges washed away by floodwaters.

Four major interstate highways were closed across North Carolina and Tennessee, with "multiple" bridges still out, said Kristin White of the US Department of Transportation.

Georgia, North Carolina and South Carolina each had more than 100 road closures, she added.

In the Georgia city of Valdosta, the storm ripped the roofs off buildings, and left road intersections a tangle of felled utility poles and trees.

"The wind started really hitting, like, felt branches and pieces of the roof hitting the side of the building and hitting the windows," said Valdosta resident Steven Mauro.

"And then we were looking out and then literally this whole street, just everything went black."

Trump, the Republican former president seeking another term, will visit Valdosta on Monday for a briefing on the disaster, his campaign said.

Biden, who has approved federal aid for several states in the wake of the disaster, intends to travel to hard-hit areas this week, "as soon as it will not disrupt emergency response operations," the White House said Sunday.

The outgoing president -- who spoke by phone Sunday with the governors of Georgia and North Carolina, as well as the mayor of Valdosta -- will speak about the post-storm response on Monday.