WASHINGTON -- The United States' top intelligence official has said a suspected Russian cyberhacking campaign constituted unprecedented meddling in the American electoral process.
Director of National Intelligence James Clapper made the assertion on January 5 at an extraordinary hearing of a leading Senate committee focusing on the question of alleged Russian interference in the presidential election campaign.
"I don't think we've ever encountered a more aggressive, a more direct effort to interfere in our elections processes than in this case," Clapper told the Senate Armed Services Committee.
The hearing is the first of several congressional inquiries looking into the scope, intent, and purpose of what Washington says was a Russia-government-orchestrated intrusion into the computer servers and e-mail accounts of U.S. political organizations.
The conclusions by U.S. intelligence agencies in October that hackers -- backed by top Russian officials -- compromised U.S. computer servers roiled the November 8 presidential vote. It also cast a shadow over Republican President-elect Donald Trump's victory over Democratic rival Hillary Clinton.
Adding to the tensions is the fact that Trump has repeatedly dismissed the intelligence assessments, which also reportedly concluded that Russia intended to help ensure victory for the president-elect, who has pledged to seek better ties with Moscow.
The Kremlin has repeatedly rejected allegations that Russia was behind the intrusions.
U.S. President-elect Donald Trump's apparent endorsement of Assange’s assertion was his latest -- and to many in Washington, his most astounding -- public challenge of the U.S. intelligence conclusions on the affair.
A day before the Senate hearing, Trump appeared to endorse a claim by Julian Assange, the founder of WikiLeaks, that Russia was not the source of the leaked e-mails that were published by the website. That endorsement drew criticism from top Democratic and Republican lawmakers.
And just before the hearing began, Trump published a series of posts on Twitter, denying he was agreeing with Assange but also suggesting that Assange's claim might be considered credible.
"I simply state what he states, it is for the people to make up their own minds as to the truth," Trump wrote. "The media lies to make it look like I am against 'Intelligence' when in fact I am a big fan!"
In a joint statement released before the hearing, Clapper and two other witnesses -- National Security Agency Director Admiral Mike Rogers and Undersecretary of Defense for Intelligence Marcel Lettre -- singled out Russia and its cyberefforts.
"We assess that only Russia's senior-most officials could have authorized the recent election-focused data thefts and disclosures," they said.
"Russia is a full-scope cyberactor that poses a major threat to U.S. government, military, diplomatic, commercial and critical infrastructure," they said.
The committee's Republican chairman, John McCain, a well-known hawk on Russian matters, has publicly endorsed the intelligence findings. He also suggested such hacking might be considered an act of war.
There is "no escaping the fact that this committee meets today for the first time in this new Congress in the aftermath of an unprecedented attack on our democracy," McCain said in opening remarks at the hearing.
Clapper, whose office coordinates the work of 17 different agencies, demurred when asked by McCain whether he agreed.
"Whether or not that constitute an act of war...is a heavy policy call that the intelligence community is not capable of making," he said. "It would certainly, in my view, carry great gravity."
U.S. Defense Undersecretary for Intelligence Marcell Lettre (left), Director of National Intelligence James Clapper (center), and National Security Agency Director Admiral Michael Rogers testify before the Senate Armed Services Committee in Washington on January 5.
Clapper told the committee that alleged hacking was only one aspect of Russian interference in the U.S. electoral process.
"It was a multifaceted campaign, the hacking was only one part of it, and it also entailed classical propaganda, disinformation, fake news," he said.
On December 9, The Washington Post reported that the CIA had determined the intent of the Russia hackers was to help Trump win the presidency, not just to undermine confidence in the U.S. electoral system.
WATCH: McCain: U.S. Inaction On Cybersecurity Has 'Emboldened Adversaries'
The New York Times later reported that intelligence officials had concluded Russian hackers accessed Republican Party computers but didn't release potentially damaging e-mails or other materials.
In contrast to Trump's announcements, the findings of the U.S. intelligence community have been publicly endorsed by President Barack Obama. On December 29, the White House announced new sanctions in response to the hacking, targeting Russia's leading intelligence agencies, the GRU and the FSB.
It also expelled 35 Russian diplomats in response to what Washington calls a campaign of harassment of its diplomats in Russia.
Obama had also ordered a full investigation of the alleged Russian hacking and promised to make it available prior to leaving office on January 20.
Clapper told the committee that he wouldn’t discuss details of the report, a classified version of which was delivered to Obama on January 5. But he said an unclassified version will be released publicly next week.
Two other Senate committees are also taking up investigations of the matter.
The Senate Foreign Relations Committee was scheduled to hear classified testimony on January 5 from Victoria Nuland, an assistant secretary of state who has been one of the Obama administration’s leading officials in dealing with the Russian government.