Donald Trump suggested the Russia investigation should end immediately, after a journalist who was among the first to report on the Trump-Russia dossier cast doubt about the document’s allegations.

“Russia Dossier reporter now doubts dopey Christopher Steele’s claims!” the president wrote in one of several tweets on the matter.

“What this means is that the FISA WARRANTS and the whole Russian Witch Hunt is a Fraud and a Hoax which should be ended immediately,” he said.

Russia Dossier reporter now doubts dopey Christopher Steele’s claims! “When you get into the details of the Steele Dossier, the specific allegations, we have not seen the evidence to support them. There’s good grounds to think that some of the more sensational allegations…..

— Donald J. Trump (@realDonaldTrump) December 18, 2018

….WILL NEVER BE PROVEN AND ARE LIKELY FALSE.” Thank you to Michael Isikoff, Yahoo, for honesty. What this means is that the FISA WARRANTS and the whole Russian Witch Hunt is a Fraud and a Hoax which should be ended immediately. Also, it was paid for by Crooked Hillary & DNC!

— Donald J. Trump (@realDonaldTrump) December 18, 2018

Michael Isikoff was the first to report Dossier allegations and now seriously doubts the Dossier claims. The whole Russian Collusion thing was a HOAX, but who is going to restore the good name of so many people whose reputations have been destroyed?

— Donald J. Trump (@realDonaldTrump) December 18, 2018

Yahoo chief investigative reporter Michael Isikoff, who met with Steele during the 2016 campaign, said this week that many of the claims in the dossier have yet to be corroborated.

Isikoff wrote an article on Sept. 23, 2016, about former Trump campaign foreign policy adviser Carter Page attracting the FBI’s attention when he allegedly tried to set up back channels between the campaign and Russia. Congressional investigations often cited the article in the debate over whether the Justice Department and FBI abused its surveillance powers by obtaining warrants on Page, a U.S. citizen, based on the unverified dossier.

Isikoff told John Ziegler’s Free Speech Broadcasting podcast this week that “some of the more sensational allegations [in the dossier] will never be proven and are likely false.”

In response to Trump’s tweet, Isikoff pointed to his book Russian Roulette, which details how Russia tried to gain influence in Washington during the 2016 election.

But here is what is true, Mr. President. https://t.co/UubCYsacAO @DavidCornDC @SkullduggeryPod https://t.co/zfGA7WUVNq

— Michael Isikoff (@Isikoff) December 18, 2018

David Corn, Isikoff’s co-author, tweeted an image of the last page of the book, in which the pair write that Trump “had aided and abetted Moscow’s attack on American democracy.”

.@realDonaldTrump To save you some time, here’s the last page of “Russian Roulette” where @Isikoff and I note you “aided and abetted Moscow’s attack on American democracy.” pic.twitter.com/AmFyPz9lOU

— David Corn (@DavidCornDC) December 18, 2018

Trump’s tweets come hours before his former national security adviser Michael Flynn is set to be sentenced for lying to the FBI about his communications with the Russian ambassador to the U.S. Trump wished Flynn good luck ahead of the hearing.