CEOs such as FB Google Twitter volunteered to testify before the Senate.

The chief executives of Facebook, Google and Twitter have voluntarily attended a hearing organized by the committee on October 28, the U.S. Senate Commerce Committee has confirmed. It will be the second time tech executives have testified before Congress this year, after a House antitrust subcommittee held hearings over the summer in the presence of the chief executives of Amazon, Apple, Google and Facebook.

The Senate Commerce Committee had previously voted unanimously to issue subpoenas forcing Facebook’s Mark Zuckerberg, Google’s Sundar Pichai and Twitter’s Jack Dorsey to testify. Although Democrats initially resisted and feared that holding such a hearing before the November 3 election might have a chilling effect, they agreed to vote for the move after the hearings were expanded.

A committee aide said the subpoenas were in place, but since the chief executives had voluntarily agreed to testify, they would not be formally issued. The chief executives of these technology companies will testify online.

CEOs such as FB Google Twitter volunteered to testify before the Senate.

The October 28 hearing will now address not only the protection of the responsibilities enjoyed by Internet companies, but also data privacy and media consolidation. The hearings come amid growing Republican protests over these liability protections, which protect Internet companies from lawsuits over user postings and give them broad leeway to adjust content.

Republicans say the protections should be scaled back, and many Democrats say they are unhappy with the actions of technology companies. Mr. Trump and his allies have accused social media companies of censoring conservative posts, a charge that technology companies have denied, as the government itself has pointed out, and has limited support for academic data. Specifically, Mr. Trump lashed out at Twitter for tagging his tweets, which included hashtags that “beautify violence” and “manipulate the media” in addition to fact-checking tags.

Many Democrats want to change the tech industry’s liability rules because they worry that social media platforms are not doing enough to combat hate speech and mis-information. Several members of the Senate Commerce Committee raised those concerns at previous meetings and said they were eager to ask the chief executives of technology companies. Senior senator Maria Cantwell, Democrat of Washington state, promised to release what she called a Democratic report on “the value of local news and unfair competition on technology platforms” before the hearing.

Aides to the committee said the hearing date was reached after repeated discussions with technology companies, noting that at one point they offered a more distant date, but it was rejected. In light of the subpoena threat, the two companies eventually agreed to allow their chief executives to testify voluntarily. Roger Wicker, chairman of the Senate Commerce Committee, said: “On the eve of a significant and competitive election, the Judiciary Committee and the American people must get a full picture of their content review practices from the heads of these companies. “