Republican officials in New Hampshire say there’s no evidence to support President Trump’s assertion of widespread voter fraud in the state, but a White House senior adviser nevertheless continues to parrot the president’s baseless claim.

“I can tell you that this issue of busing voters into New Hampshire is widely known by anyone who’s worked in New Hampshire politics,” Stephen Miller, a 31-year-old Trump adviser with a long history of supporting ultra-nationalist policies, said during an appearance on ABC’s This Week. “It’s very real. It’s very serious.”

“This morning, on this show, is not the venue for me to lay out all the evidence,” Miller added, refusing to back up his claim despite calls from host George Stephanopoulos to do so.

“But, for the record, you have provided zero evidence that the president was the victim of massive voter fraud in New Hampshire,” Stephanopoulos said.

The segment was in response to a Politico report from last week that claimed Trump suggested without evidence during a closed-door meeting that he and former Sen. Kelly Ayotte (R-NH) would have won in New Hampshire had it not been for “thousands” of people “brought in on buses” from Massachusetts to vote fraudulently.

Trump’s unfounded voter fraud claims are pushed by the conspiracy theory site known as InfoWars, an outlet that, among other claims, charges that the federal government has a “weather weapon” that “can create and steer groups of tornadoes.”

Along with fact checkers, elections officials in the state were quick to throw cold water on Trump’s baseless assertion. Attorney General Joseph Foster told WMUR.com in response to Trump that the state had “seen no evidence of large-scale voter fraud whatsoever, and none has been brought to our attention.”

“Repeating: there is no voter fraud in NH. None. Zip. Nada. Hundreds of lawyers, poll workers, watchers, press—no buses rolled in,” tweeted Steve Duprey, national committeeman for New Hampshire’s Republican State Committee.

“Let me be as unequivocal as possible: allegations of voter fraud in NH are baseless, without any merit—it’s shameful to spread these fantasies,” tweeted Tom Rath, former attorney general of New Hampshire.

Fact-checking website PolitiFact rated a similar claim by New Hampshire Republican Gov. Chris Sununu a “pants on fire” falsehood when he made the assertion in November in what was seemingly a jab at the state’s same-day voter registration policy. “While New Hampshire has experienced instances of voter fraud, the state’s top election official says they have been isolated and amount to one or two cases a year,” the site concluded. “Sununu’s claim is ridiculous.”

Sununu walked back his comments, claiming he didn’t “want to imply” he saw buses and that the claim he made was “more a figure of speech.” New Hampshire Republicans, including the governor, have nevertheless signaled their intent to roll back the state’s same-day voter registration.

Fourteen states and the District of Columbia allow voters to register and cast ballots on the same day, according to the National Conference of State Legislatures. All states require proof of residency to register to vote, and some states—like New Hampshire—have additional measures to prevent fraud.

Studies show that allowing same-day voter registration increases voter turnout. It also “remedies inaccurate voter rolls” according to Project Vote—something Miller identified as an issue during his Sunday interview on ABC.