President Joe Biden and first lady Jill Biden in a video message on Monday told those affected by Hurricane Helene that "we grieve with you” and "the nation has your back."

The Bidens said the Federal Emergency Management Agency was working to help those in need across several states.

"FEMA is knocking on doors to sign up survivors for direct and immediate financial aid, because many of them need it now," the president said. "And I've directed my team to stay there 24/7 with you, until this job is done."

The storm made landfall in Florida last week as a massive Category 4 hurricane. As it moved through the southeastern United States it killed some 230 people, The Associated Press reported, with hundreds of others still unaccounted for.

The storm, which was the deadliest mainland hurricane since Katrina in 2005, churned through Florida, Georgia, North Carolina, South Carolina, Virginia, Tennessee and Alabama.

Officials in Buncombe County, North Carolina, said Sunday their primary search is 90% complete.

At a news conference, officials said they are using K-9 units as they search piles of debris for victims in the search and recovery operation. Fourteen urban search and rescue teams, including eight federal, are actively searching the area, officials said.

Most of the roads -- an estimated 90% -- are open to emergency vehicles, authorities said at the briefing.

The Army Corps of Engineers is helping to work on the damaged water infrastructure along with 160 city water employees in Asheville, and four contractors, according to officials.

-ABC News' Bill Hutchinson

The death toll from Hurricane Helene inched past 230 people on Saturday, The Associated Press reported.

The grim task of recovering bodies continued more than a week after the monster storm ravaged the southeast, killing people in six states.

The number of deaths stood at 225 on Friday; two more were recorded in South Carolina the following day.

It was still unclear how many people were unaccounted for or missing, and the toll could rise even higher.

-ABC News’ Victoria Arancio

President Joe Biden has ordered the deployment of 500 more troops to western North Carolina to aid in Hurricane Helene recovery efforts, he announced in a statement Sunday.

Earlier this week, Biden ordered 1,000 active-duty service members to be deployed to the area. According to the White House statement, the Biden administration has sent more than $137 million in federal funding to aid in recovery efforts, "with more to come."

"With a total of 1,500 troops now supplementing a robust on-the-ground effort -- including more than 6,100 National Guardsmen and more than 7,000 Federal personnel -- my Administration is sparing no resource to support families as they begin their road to rebuilding," Biden said.

According to Pentagon Press Secretary Maj. Gen. Pat Ryder, these soldiers are working with FEMA, the National Guard and state officials to support North Carolina by helping distribute commodities and clearing emergency routes.

Hundreds of thousands of customers in the South are still without power over one week after Hurricane Helene made landfall.

More than 277,000 customers are in the dark in South Carolina and 230,000 are without power in North Carolina.

Another 200,000 are without power in Georgia.

"This has been a historic storm. We've never seen anything like this," Duke Energy spokesperson Bill Norton said. “The biggest challenge has been the unprecedented flooding. It’s not just poles and wires that are down -- it's the backbone of our system, the transmission infrastructure and substations."

Duke Energy has a "crew of 21,000 line workers, vegetation crews and more across the Carolinas," Norton said.

In North Carolina, crews have repaired more than 1.2 million power outages and are on track to restore an additional 27,000 customers by Friday night and another 69,000 in the hardest-hit areas by Sunday evening, Norton said on Friday.

The water line is almost to the top of the substation that serves Biltmore Village, North Carolina, and the substation will take three to four months to repair, Norton said.

Crews have wheeled in a 200,000-pound mobile substation to serve in the interim, Norton said, noting that it was a "slow, meticulous" process to get the mobile substation to the region because crews had to make sure the bridges hit by Helene could withstand it.

The mobile substation "will effectively allow us to bypass the substation for the next three to four months as we level it and build it again on higher ground," Norton said. "Those customers will have power even as we rebuild that substation."