Facebook CEO Mark Zuckerberg and Twitter CEO Jack Dorsey have agreed to testify before Congress on Oct. 28. Google CEO Sundar Pichai has also accepted, a report late Friday said. The news comes a day after the US Senate's Commerce committee voted unanimously to subpoena the appearances of Zuckerberg, Pichai and Dorsey. The CEOs agreed to appear without being subpoenaed, according to The Washington Post Friday.

The hearing relates to changes being considered to Section 230 of the 1996 Communications Decency Act. Section 230 is considered the most important law protecting speech online. It prevents social media platforms, such as Facebook and Twitter, and internet providers, such as Verizon and Comcast, from lawsuits over posts made by users on their services.

Twitter began labelling President Donald Trump's tweets in in May, flagging them as being "potentially misleading." The situation culminated in Trump signing an executive order targeting social media platforms like Twitter and Facebook. The order resulted in the Justice Department last week unveiling its proposal to amend Section 230 to remove protections for online platforms.

"Jack has voluntarily agreed to testify virtually before the Senate Commerce Committee on October 28 — less than a week before the US Presidential Election," Twitter confirmed in a tweet. "We've made our views clear on reactionary and politicized attempts to erode #Section230. They threaten the future of online speech and Internet freedoms. Reasoned and productive debate is essential."

Facebook confirmed Zuckerberg's appearance, but declined to comment. Google didn't immediately respond to a request for comment. Both Zuckerberg and Pichai made virtual appearances before a House antitrust subcommittee in July, along with Amazon CEO Jeff Bezos and Apple CEO Tim Cook.