Updated Feb. 18 at 9 a.m. ET
President Trump chided his national security adviser on Sunday, tweeting that H.R. McMaster "forgot to say that the results of the 2016 election were not impacted or changed by the Russians."
McMaster said on Saturday that it is now "incontrovertible" Russia interfered in the 2016 election.
McMaster, who spoke a day after a federal grand jury indicted more than a dozen Russians in connection with the interference, was addressing an international audience at the Munich Security Conference, including several Russian officials.
"As you can see with the FBI indictment, the evidence is now really incontrovertible and available in the public domain, whereas in the past it was difficult to attribute," he said.
McMaster's remarks were notable, in part, because they appeared to fly in the face of his boss's oft-repeated claims about the investigation being a phony witch hunt.
In a separate tweet Sunday, Trump essentially denied ever denying Russia's involvement.
"I never said Russia did not meddle in the election, I said 'it may be Russia, or China or another country or group, or it may be a 400 pound genius sitting in bed and playing with his computer,'" he wrote. "The Russian 'hoax' was that the Trump campaign colluded with Russia - it never did!"
On Saturday, McMaster did not equivocate. He used forceful language to convey American strength against what the indictment describes as a coordinated Russian disinformation campaign, waged largely online, meant to sway American voters in Trump's favor.
"The United States will expose and act against those who use cyberspace, social media and other means to advance campaigns of disinformation, subversion and espionage," McMaster said.
He emphasized the need for the West to come together to defend itself against such scourges.
"We are already improving our ability to defeat these pernicious threats," McMaster added, citing as an example The European Centre of Excellence for Countering Hybrid Threats, of which the U.S. is a member.
In responding to a question from a Russian politician about the U.S. and Russia potentially working together on cybersecurity, McMaster seemed to dismiss the notion.
"I'm surprised there are any Russian cyber experts available, based on how active most of them have been in undermining our democracies in the West," he said to chuckles from the audience. He added, "We would love to have a cyber dialogue when Russia is sincere about curtailing its sophisticated form of espionage."
McMaster's remarks came in sharp contrast to Russian Foreign Minister Sergey Lavrov, who spoke minutes earlier from the same stage and brushed off the indictment, calling it through an interpreter "just blabber."
The New York Times reports that Lavrov attempted to bolster his case that Russia has done nothing wrong by citing Vice President Pence's earlier assessment of the FBI investigation.
Pence told Axios on Wednesday, "irrespective of efforts that were made in 2016 by foreign powers, it is the universal conclusion of our intelligence communities that none of those efforts had any effect on the outcome of the 2016 election."
But as former Director of National Intelligence James Clapper told NPR, "The intelligence community has neither the authority nor the capability to make such a judgment as to whether there was or was not impact on the election. And we did not say that."
On Friday, shortly after the indictment was announced, President Trump conceded in a tweet that Russia did carry out an "anti-US campaign," but he said it began well before he launched his presidential run. "The results of the election were not impacted. The Trump campaign did nothing wrong - no collusion!" he wrote.
Deputy Attorney General Rod Rosenstein, who oversees the investigation, said Friday there is "no allegation in this indictment that any American was a knowing participant in this illegal activity" and "no allegation that this activity actually altered the outcome of the 2016 election."
On Sunday Trump implied in a tweet that the investigation itself plays right into Russia's plans.
"If it was the GOAL of Russia to create discord, disruption and chaos within the U.S. then, with all of the Committee Hearings, Investigations and Party hatred, they have succeeded beyond their wildest dreams," he wrote. "They are laughing their asses off in Moscow. Get smart America!"