A reporter, who was among the first to report on former British intelligence agent Michael Steele’s dossier alleging ties between the Trump campaign and Russian officials, said in an interview some of the dossier’s “more sensational allegations” are “likely false.”

Michael Isikoff, the chief investigative correspondent for Yahoo News, said Saturday during an interview on conservative commentator John Ziegler's "Free Speech Broadcasting" podcast that "Steele was clearly onto something" in his probe into the campaign's Russian connection but evidence has not surfaced to support some of his specific assertions.

Steele was correct to suspect "that there was a major Kremlin effort to interfere in our elections, that they were trying to help Trump's campaign, and that there were multiple contacts between various Russian figures close to the government and various people in the Trump campaign," Isikoff said.

More:Senate reports find millions of social media posts by Russians aimed at helping Trump, GOP

But he said when "you actually get into the details of the Steele dossier, the specific allegations, we have not seen the evidence to support them, and, in fact, there's good grounds to think that some of the more sensational allegations will never be proven and are likely false."

"It's a mixed record at best," he said. "Things could change. Mueller may yet produce evidence that changes this calculation but based on the public record at this point, I'd have to say that most of the specific allegations have not been borne out."

Steele was contracted by the research firm Fusion GPS to conduct opposition research on Trump, first for a conservative website and later for the Democratic National Committee and the Clinton campaign. His work helped spark the investigation into Russian meddling in the 2016 election, which in turn led to the appointment of special counsel Robert Mueller.

Among the dossier's unsubstantiated claims is a salacious one that Russian intelligence had compromising film of Trump with prostitutes.

Ignoring Isikoff's statement that there was evidence of ties between his campaign and Russian officials, President Donald Trump thanked the reporter for his "honesty" in a tweet Tuesday.

Trump asserted incorrectly that Isikoff's opinion means "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! "

Republicans on Capitol Hill and conservative commentators have questioned the legitimacy of Mueller's probe and the entire Russia investigation because the FBI relied on the dossier's allegations to obtain a FISA warrant to surveil Trump campaign adviser Carter Page. But four federal judges separately signed off on the warrants and there has been no evidence to show investigators acted improperly in obtaining them.

Redacted versions of the warrant applications show that the FBI did base its request in part on Steele’s information, whom they said had given them reliable information in the past. It also cited Page’s links to Russian intelligence officials. Isikoff's reporting, which used Steele as a source, was also mentioned.

More:FBI releases FISA records on Carter Page surveillance

"But here is what is true, Mr. President," Isikoff replied to Trump in a tweet linking to his 2018 book "Russian Roulette: The Inside Story of Putin's War on America and the Election of Donald Trump," which he co-authored with Mother Jones reporter David Corn.

“During the campaign, Trump had encouraged Russia’s hacking and dumping – of which he was the chief beneficiary,” the book concludes. “Whether or not the investigations would ever turn up hard evidence of direct collusion, Trump’s actions – his adamant and consistent denial of any Russian role – had provided Putin cover. In that sense, he had aided and abetted Moscow’s attack on American democracy.”

Isikoff made his remarks during a discussion with Ziegler about a claim made by Trump’s former personal attorney Michael Cohen. Cohen said Trump was in the room during a discussion with National Enquirer publisher David Pecker about how the newspaper could help kill negative stories about the then-candidate.

Ziegler suggested the National Enquirer story was the "real scandal" out of the Trump campaign because it revealed that a tabloid might possess material that could theoretically be used to blackmail a sitting president.

"The irony here is Steele may be right but it wasn't the Kremlin that had the sexual kompromat on Donald Trump, it was the National Enquirer," Isikoff said. He added that Pecker could be a key witness for House Democrats when they take control of that chamber next month.

Contributing: Brad Heath