Washington DC - President Joe Biden and Vice President Kamala Harris are heading Wednesday to areas devastated by Hurricane Helene, after Harris's election rival Donald Trump sought to turn their handling of the disaster into campaign fodder.

Biden will survey damage by helicopter over the flood-hit city of Asheville, North Carolina, one of the places worst hit by the storm's deadly rampage through the southeastern US.

He will also visit a rescue command center in the state, where more than 70 people were killed.

Before departing Washington, Biden announced the deployment of up to 1,000 active-duty soldiers to North Carolina to boost emergency response efforts, including the "fight to save lives" in the devastated communities.

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"These soldiers will speed up the delivery of life-saving supplies of food, water, and medicine to isolated communities in North Carolina," the president said in a statement.

"My heart goes out to everyone who has experienced unthinkable loss," he added. "We are here for you -- and we will stay here for as long as it takes."

The federal response in the region already tops 3,000 personnel, including National Guard members, emergency responders, health workers, and debris-clearing and power-restoration experts.

Harris, who replaced Biden as the Democratic presidential nominee for the November 5 election, will travel separately to the southern state of Georgia, which has also been badly hit.

Officials say Helene has killed at least 155 people and left hundreds unaccounted for across several states.

Deluges triggered by Helene have caused huge devastation in the region of the Appalachian mountains, with towns and villages cut off from the rest of the world.

Biden said he had not traveled earlier because rescue workers said his visit would have affected operations. He will also travel to Florida, where the storm roared ashore as a Category 4 hurricane, and Georgia in the coming days, the White House said.

North Carolina and Georgia are two of the seven crucial swing states that are likely to decide the result of the US election. Early voting has already begun in several states.

The visits come a day after the vice presidential candidates, Republican JD Vance and Democrat Tim Walz, faced off in a surprisingly civil debate – the last scheduled on-stage showdown before election day.

The pair acknowledged common ground on multiple issues, including about those suffering from the storm, with Vance saying: "We want as robust and aggressive a federal response as we can get to save as many lives as possible."

But Republican former president Trump earlier sought to make political capital out of the disaster, accusing the administration, without evidence, of ignoring the crisis and denying help to his supporters.

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Trump made his way to the disaster zone Monday, visiting the stricken town of Valdosta, Georgia, and vowing to "bring lots of relief material, including fuel, equipment, water, and other things."

"He's lying" about government inaction, Biden told reporters Monday in the Oval Office, adding he had spoken to North Carolina Governor Roy Cooper "and he told him he's lying. I don't know why he does it... that's simply not true, and it's irresponsible."

Cooper has described the flooding's devastation as "beyond belief," with communities "wiped off the map."

The political storm over Helene comes as Biden and Harris weather a series of crises with barely a month until the knife-edge election.

As they coordinate hurricane response, Biden and Harris are also dealing with Iranian missile attacks on Israel that have further fueled tensions in the Middle East.

The White House is also trying to resolve a strike by US dockworkers that threatens the economy – with the three crises giving rise to talk of a feared "October surprise" that could influence the election.