It remains unclear what, if any, onerous regulations may eventually befall companies such as Google, Facebook and Twitter.
Facebook FB.O fell 1.6 percent and Twitter TWTR.N 5.2 percent.
Investors were seemingly unimpressed by the execs' statements ー shares of Facebook, Twitter, and Dorsey's other company Square were all down along with the broader social media and tech space midday.
Lawmakers instead questioned Twitter CEO Jack Dorsey and Facebook Chief Operating Officer Sheryl Sandberg about steps their companies are taking to reduce foreign platform manipulation on their platforms.
Thirteen Russians were indicted earlier this year on charges of an elaborate social media plot to disrupt the 2016 U.S. presidential election.
"Congress is going to have to take action here", said Warner.
Trump told the conservative outlet in an interview conducted on Tuesday that "I think they already have" interfered in the November 6 election. Both Senate Intelligence Committee Richard Burr, R-North Carolina, and Vice Chairman Mark Warner, D-Virginia, lambasted Google for failing to sent a top representative.
The afternoon hearing before the House Energy and Commerce Committee was to focus on bias and Twitter's algorithms.
Trump Lobbying GOP Senators to Turn Against Sessions
Justice Department lawyers have previously said Rosenstein is aware of the scope and activities of Mueller's investigation. Trump has raged against Jeff Sessions since his decision to recuse himself from Russia-related matters a year ago .
Dorsey and other tech titans will be in the USA capital on Wednesday to testify in front of the Senate Intelligence Committee, which is still probing Russian interference in the 2016 election, along with the general growing influence of social media to disseminate information.
Google says Walker will still submit testimony and brief members on the subject of the hearing, which is foreign influence operations and their use of social media platforms.
"We've removed hundreds of pages and accounts involved in coordinated inauthentic behavior - meaning they misled others about who they were and what they were doing", Sandberg said.
During Wednesday's hearing, Sandberg reiterated that such threats would continue and that Facebook would keep working to address them.
The testimony comes as some Republicans say conservatives have been censored on social media.
President Donald Trump used Twitter on July 26 to fault the website, without evidence, for using so-called shadow banning, or limiting the visibility of, prominent Republicans.
Republicans control majorities in both the Senate and House, but the House's approach to the election issue has been far more partisan than the Senate's.
Wednesday's hearing was a follow-up to one held in November that focused on foreign government manipulation of social media platforms to influence USA politics.
Senate leaders rejected Google's offer to make Kent Walker, its senior vice president and chief legal officer, available for the hearings.