A slew of falsehoods about Hurricane Helene, including claims of funds diverted from storm survivors to migrants and even that Democrats somehow directed the hurricane itself, have hampered the response to one of the deadliest hurricanes to ever hit the US, the nation’s top emergency official has warned.

Misinformation spread by Donald Trump, his supporters and others about the hurricane has shrouded the recovery effort for communities shattered by Helene, which tore through five states causing at least 227 deaths and tens of billions of dollars of damage. Many places, such as in western North Carolina, are still without a water supply, navigable roads or vital supplies.

“It’s frankly disappointing we are having to deal with this narrative, the fact there are a few leaders having a hard time telling the difference between fact and fiction is creating an impedance to our ability to actually get people the help they need,” Deanne Criswell, administrator of the Federal Emergency Management Agency (Fema), told MSNBC on Monday.

Trump has accused Joe Biden’s administration of “abandoning” people to the crisis and, baselessly, of being short of disaster relief funds due to money spent on undocumented migrants. Such claims are “frankly ridiculous” and creating a “truly dangerous narrative that is creating this fear” among affected people, Criswell said.

In multiple rallies in the past week, Trump has accused Biden and Kamala Harris of favoring migrants over disaster-hit areas. “They stole the Fema money, just like they stole it from a bank, so they could give it to their illegal immigrants that they want to have vote for them this season,” Trump has said.

“Kamala spent all her Fema money, billions of dollars, on housing for illegal immigrants.” Trump added the places worst hit are “largely a Republican area so some people say they did it for that reason”.

JD Vance, Trump’s Republican running mate, echoed this theme on Monday, telling Fox News that Fema’s focus on migrants is “going to distract focus from their core job of helping American citizens in their time of need”. Last week, Stephen Miller, a far-right Trump adviser, said that “Kamala Harris turned Fema into an illegal alien resettlement agency”.

Fema does, in fact, have a housing program that offers shelter to migrants leaving detention but this is separate from its disaster relief program. “No money is being diverted from disaster response needs. None,” the White House has stated.

In remarks on Monday after speaking to Criswell by phone, Harris urged politicians to stop “playing games” with lives at stake. According to the White House pool, the vice-president said: “There’s a lot of misinformation being pushed out there by the former president about what is available, particularly for the survivors of Helene. First of all, it’s extraordinarily irresponsible. It’s about him, it’s not about you. The reality is Fema has so many resources that are available to those who desperately need them.”

Congress recently provided an extra $20bn for disaster relief but Biden has warned that more funding will be needed to help the long-term recovery of places increasingly assailed by powerful storms fueled by global heating.

Other conspiracy theories and erroneous claims have swirled online and in areas affected by Helene, such as the assertion that Fema will give only $750 to individuals as a loan (it is, in fact, a grant, and can be followed by further claims for more than $40,000) or that the agency is seizing people’s land.

Fema has, unusually, put up a web page to counter these claims, with a spokesman saying the misinformation is “extremely damaging” to response efforts as it deters people from seeking assistance. “We are going to continue to message aggressively so everyone understands what the facts are,” he said regarding the looming Hurricane Milton, which is set to hit Florida.

Some social media posts spreading misinformation about the hurricanes called for militias to be formed to confront Fema workers, while other posts contained antisemitic hatred aimed at figures such as Esther Manheimer, mayor of Asheville, North Carolina, a city badly affected by the storm.

“It’s surprising to me how this is developing but unfortunately it seems antisemitic hate speech is becoming more common in the United States today,” Manheimer said.

“I’ve tried to steer clear of X and other platforms but there is a lot of misinformation that people tend to believe. We’ve had people in the community reaching out to ask if false things are true because folks are intentionally misleading them.”

Manheimer said that Asheville, including her own home, still lacks running water but is being “overwhelmed” with support by Fema to clear roads and get power back on.

“People have lost everything here and the last thing we need is for people to spread false information,” she said. “There are talking points being distributed throughout the Republican party that just aren’t correct. They seem to think spreading misinformation will help win this election.”

One of the more outlandish claims about the hurricane came from Marjorie Taylor Greene, the extremist Republican congresswoman who previously claimed that Jewish lasers from space caused forest fires. “Yes they can control the weather,” Greene posted on X about the hurricane last week. “It’s ridiculous for anyone to lie and say it can’t be done.”

Andrew Dessler, a climate scientist at Texas A&M University, said: “There is no mechanism to control a hurricane and no evidence that anyone was trying to modify it. This is just a crazy conspiracy theory.”

“While humans don’t ‘control’ the weather we are affecting the weather. Human activities, mainly the emission of greenhouse gases, did indeed make Helene more destructive.”

He added: “If she wants humans to stop affecting the weather she should support phasing out fossil fuels.”

So far, Biden has declared the federal government will pay for the entire cost of activities such as debris removal, search and rescue and food supplies for Florida, Georgia, North Carolina, South Carolina, Tennessee and Virginia. The president has also already approved disaster help for Florida ahead of Milton’s arrival.

This approach has garnered some rare praise for Biden from Republican governors of affected states, with some Republican lawmakers calling for the conspiracy theories to abate.

“Will you all help STOP this conspiracy theory junk that is floating all over Facebook and the internet about the floods,” Kevin Corbin, a Republican state senator for western North Carolina, posted on Facebook last week. “Please don’t let these crazy stories consume you or have you continually contact your elected officials to see if they are true.”