Dianne Feinstein threatens tech execs on Russian propaganda: ‘Do something about it -- or we will’
Sen. Dianne Feinstein (C-SPAN)

Sen. Dianne Feinstein (D-CA) issued a stern warning to Silicon Valley officials during a hearing on Russian disinformation campaigns during the presidential election.

The California Democrat questioned officials from Facebook, Google and Twitter for the second day of hearings Wednesday on their role in helping Russia spread propaganda intended to interfere with the election.

"I must say, I don't think you get it," Feinstein said. "What we're talking about is a cataclysmic change. What we're talking about is the beginning of cyber warfare. What we're talking about is a major foreign power with the sophistication and ability to involve themselves in a presidential election and sow conflict and discontent all over this country. We are not going to go away, gentlemen. This is a very big deal."

Lawmakers from both parties complained after Tuesday's hearing before a Senate Judiciary subcommittee that the social media companies had waited nearly a year to publicly admit how many Americans had been exposed to Russian propaganda through their services.

Senators want the companies to regulate their advertising practices similar to rules for political ads on television, among other suggestions -- and Feinstein warned Congress would act if they did not.

"I went home last night with profound disappointment," Feinstein said. "I asked specific questions, I got vague answers. That just won't do. You have a huge problem on your hands."

She said the United States would be the first country to bring Russian "fake news" to their attention, although Ukrainian officials say they warned Facebook about the problem at least two years ago but were blown off.

"You bear this responsibility," she said. "You have created these platforms, and now they are being misused, and you have to be the ones to do something about it -- or we will."