WASHINGTON — A bipartisan panel of US senators Tuesday called for sweeping action by Congress, the White House, and Silicon Valley to ensure social media sites aren’t used to interfere in the coming presidential election, delivering a sobering assessment about the weaknesses that Russian operatives exploited in the 2016 campaign.

The Senate Intelligence Committee, a Republican-led panel that has been investigating foreign electoral interference for more than two and a half years, said in blunt language that Russians worked to damage Democrat Hillary Clinton while bolstering Republican Donald Trump — and made clear that fresh rounds of interference are likely ahead of the 2020 vote.


‘‘Russia is waging an information warfare campaign against the US that didn’t start and didn’t end with the 2016 election,’’ said Senator Richard Burr, Republican of North Carolina, the committee’s chairman. ‘‘Their goal is broader: to sow societal discord and erode public confidence in the machinery of government. By flooding social media with false reports, conspiracy theories, and trolls, and by exploiting existing divisions, Russia is trying to breed distrust of our democratic institutions and our fellow Americans.’’

In response, Democratic and Republican lawmakers urged their peers in Congress to act, exploring the adoption of new regulations that would make political ads more transparent. They also called on the White House and the executive branch to adopt a more forceful, public role, warning Americans about the ways in which dangerous misinformation can spread while creating new teams within the US government to monitor for threats and share intelligence with industry.

The recommendations for Silicon Valley call for more extensive sharing of intelligence among companies, in recognition of the shortage of such sharing in 2016 and also the ways that disinformation from Russia and other countries spreads across numerous platforms — with posts linking back and forth in a tangle of connections.


‘‘The Committee found that Russia’s targeting of the 2016 US presidential election was part of a broader, sophisticated and ongoing information warfare campaign designed to sow discord in American politics and society,’’ the report says. The Russian effort was ‘‘a vastly more complex and strategic assault on the United States than was initially understood... an increasingly brazen interference by the Kremlin on the citizens and democratic institutions of the United States.’’

The committee report recounts extensive Russian manipulation of Facebook, Instagram, YouTube, Twitter, Google, and other major platforms with the goal of dividing Americans, suppressing African American turnout, and helping elect Trump president. But Tuesday’s report, the second volume of the committee’s final report on Russian interference in the 2016 election, offered the most detailed set of recommendations so far in attempting to bolster the nation’s defenses against foreign meddling online — now a routine tactic for many nations.

While the report tracked closely with the previous findings of Special Counsel Robert Mueller and several independent researchers, the comprehensiveness and forcefulness of the report’s conclusions are striking in light of Trump’s efforts to minimize the impact of Russian interference in the election that brought him to office. The release also comes amid a burgeoning impeachment inquiry over whether Trump sought foreign help — from Ukraine and others — in seeking to bolster his reelection chances in 2020.

The White House did not immediately respond to requests for comment.

Trump has questioned the findings by US intelligence officials that the 2016 election was a target of Russian manipulation, sometimes embracing conservative conspiracy theories even as federal investigators have detailed efforts to interfere through fake social media accounts, leaks of stolen Democratic Party documents and hacks into state voting systems.


The Senate Intelligence Committee backed the views of other federal officials regarding the sweep and goals of the Russian effort saying that the operation ‘‘sought to influence the 2016 US presidential election by harming Hillary Clinton’s chances of success and supporting Donald Trump at the direction of the Kremlin.’’

The White House, say numerous researchers and outside critics, has failed to lead the kind of aggressive, government-wide effort they argue would protect the 2020 race, though some federal agencies took steps to address foreign threats more forcefully during the 2018 congressional election.

That included a cyber-operation that disrupted Russia’s Internet Research Agency, based in St. Petersburg, on election day. Mueller indicted the agency and 13 affiliated Russians for their alleged role in 2016 election interference, which played a central role as well in Mueller’s landmark final report, released in April.

‘‘With the 2020 elections on the horizon, there’s no doubt that bad actors will continue to try to weaponize the scale and reach of social media platforms to erode public confidence and foster chaos,’’ said Senator Mark Warner of Virginia, the top Democrat on the committee. ‘‘The Russian playbook is out in the open for other foreign and domestic adversaries to expand upon — and their techniques will only get more sophisticated.’’


Lawmakers delivered their recommendations just days after new revelations of possible election interference jolted Washington. On Friday, Microsoft announced it had discovered Iranian-linked hackers had targeted the personal email accounts associated with a number of current and former government officials, journalists writing on global affairs, and at least one presidential candidate’s campaign.

Microsoft declined to name the affected campaign, and said the account was not compromised. Still, the Iranian effort highlighted the lingering aftermath of Russia’s online efforts three years ago, as other countries around the world now seek to adopt the Kremlin’s tactics, turning disinformation and other forms of election meddling into a global phenomenon.

Iran has joined Russia as a leader in foreign online interference. The list of countries known to have conducted such operations also includes Saudi Arabia, Israel, China, the United Arab Emirates, Pakistan, and Venezuela, say researchers. A report by Oxford University’s Computational Propaganda Project said last month that at least 70 nations have sought to manipulate voters and others online, though most meddle mainly in their own domestic politics.