Donald Trump refuses to back down from his claim, which has been made without specific evidence, that the upcoming election results will be rigged at polling places.

The Republican nominee for President tweeted on Sunday that the election was being rigged at polling places, just hours after his running mate, Governor Mike Pence, told Chuck Todd on NBC’s Meet the Press that he will accept Election Day results.

The election is absolutely being rigged by the dishonest and distorted media pushing Crooked Hillary – but also at many polling places – SAD

— Donald J. Trump (@realDonaldTrump) October 16, 2016

Speaker of the House Paul Ryan on Saturday criticized Trump for questioning the validity of the electoral process.

“Our democracy relies on confidence in election results, and the Speaker is fully confident the states will carry out this election with integrity,” Ryan spokesperson AshLee Strong said.

Other party supporters have stood by Trump’s claims, which have emerged in recent days as the candidate illustrated far-fetched imagined plots to defeat him to explain his sinking poll numbers.

Former House Speaker Newt Gingrich said on ABC’s This Week, blaming the “unending one-sided assault of the news media” for the election being rigged. Gingrich said the rigging is not happening at the local level, though he encouraged voters to monitor polling places.

Trump adviser Rudy Giuliani said on Sunday that Democrats could steal an extremely close election by having supposedly dead people vote in inner cities.

“I’m sorry, dead people generally vote for Democrats rather than Republicans,” Giuliani said on CNN’s State of the Union. “You want me to [say] that I think the election in Philadelphia and Chicago is going to be fair? I would have to be a moron to say that.”