White House chief of staff Reince Priebus on Sunday refuted Russian claims that President Donald Trump accepted Russian President Vladimir Putin’s assurances that Russia did not meddle in the 2016 U.S. presidential election.

During the presidents’ two-hour meeting on Friday at the G-20 Summit in Germany, according to Russian Foreign Minister Sergey Lavrov, Trump accepted Putin’s claims that Russia had nothing to do with cyberattacks aimed at influencing the outcome of the American election.

Speaking with reporters on board Air Force One during the return flight to Washington on Saturday, top administration officials did not dispute Lavrov’s account—instead putting the focus on Trump’s desire to work with Putin on global conflicts including Syria and Ukraine. That changed on Sunday.

“The president absolutely did not believe the denial of President Putin,” Priebus, who was not in the room for the two-hour meeting at the G-20 Summit in Germany, said on Fox News Sunday.

“This was not just a five-minute piece of the conversation. This was an extensive portion of the meeting. And after going after it with President Putin more than once—two times maybe even three times—the president at that point, after spending a large portion of the meeting on the subject, moved on to other topics,” Priebus added.

Lavrov’s assertion was met with almost immediate skepticism, but Trump’s recent public statements have fueled criticism over how seriously he takes the issue of Russian meddling—on which there is unanimous agreement among Trump’s intelligence chiefs.

The president tiptoed around the issue earlier in the week during a press conference alongside the Polish president, saying “nobody really knows for sure” whether Russia interfered in the electoral process. In a separate remark, Trump said “I think it was Russia” but “it was probably others also.” Priebus repeated this claim on Fox News Sunday.

“He said they probably meddled in the election. They did meddle in the election,” Priebus added. “The one thing that he also says, which drives the media crazy but it’s an absolute fact, is that others have as well. And that’s true.”

U.S. intelligence agencies have concluded not only that Russia intervened, but that the Kremlin-ordered operation was carried out with the goal of benefitting Trump. The president has kept the focus on recent Washington Post reporting about former President Barack Obama’s reluctance to confront Russia’s actions more forcefully and openly during the run-up to the election.

In an approach markedly different from Priebus’, former Trump campaign manager Corey Lewandowski said on Fox & Friends Sunday morning that the issue of Russian meddling is “officially dead” because of Putin’s denial. Four separate congressional committees and a Justice Department special counsel are investigating Russian interference.

After the American and Russian leaders met on Friday, U.S. Secretary of State Rex Tillerson said both nations want to “move forward from something that may be an intractable disagreement at this point.”

Earlier Sunday, Trump said on Twitter that Putin “vehemently denied” having meddled in the election, adding that he pressed the Russian leader on the issue twice. Trump also said he and Putin “discussed forming an impenetrable Cyber Security unit so that election hacking, & many other negative things, will be guarded and safe”—a suggestion that was met with mockery from top Republican senators.

“Partnering with Putin on a ‘Cyber Security Unit’ is akin to partnering with Assad on ‘Chemical Weapons Unit,’” Florida Sen. Marco Rubio said, referring to Syrian President Bashar al-Assad.