Facebook and Twitter have both agreed to appear in front of the United States Congress and testify publicly as part of the ongoing investigation into Russian interference during the 2016 presidential election, Recode reported.

The hearing is scheduled to take place before the Senate Intelligence Committee on Nov. 1. Google has also been invited to testify during the hearing but has yet to publicly respond to the invitation.

Neither Twitter nor Facebook have announced if their CEOs—Jack Dorsey at Twitter and Mark Zuckerberg at Facebook—will testify in front of the committee.

Facebook may tap chief security officer Alex Stamos to stand in front of the Senate, as he has headed up the company’s internal campaign to track down information about Russia-bought advertising that has appeared on the social network.

Twitter may send Colin Crowell, the company’s vice president for global public policy, to speak before the members of the Senate Intelligence Committee. Crowell has briefed members of the House and Senate on matters regarding Twitter’s participation in the investigation.

The major social networks, which have a disproportionate amount of influence in the world of online advertising, have rarely been pressed publicly on their role as influencing platforms but have come under increased scrutiny as more information has been revealed about Russian efforts to interfere with the 2016 U.S. presidential election.

Last month, Facebook revealed that it discovered at least $100,000 in ad spending from June 2015 to May 2017, which were linked to 3,000 ads. The propaganda was traced back to nearly 500 inauthentic accounts and pages operated out of Russia.

The social network provided information about the advertising campaign to Congress as well as to FBI Special Counsel Robert Mueller, who is heading up the independent investigation into links between the Russian government and individuals associated with the campaign of President Donald Trump.

Recent reports have suggested the advertisements purchased by Russia and run on Facebook during the 2016 campaign reached as many as 10 million Americans, and about half of the ads were seen before the presidential election.

Last week, Twitter agreed to hand over information to Congress about accounts on the platform that may have been used for malicious purposes or for misinformation during the election.

Twitter disclosed a total of 22 accounts to Congress that were connected in some way to similar Russia-backed accounts discovered on Facebook. Those 22 accounts led the company to another 179 related or linked accounts, which were removed after being found to be in violation of the social media platform’s rules. The company also said none of the accounts were registered advertisers on the site.

"As we noted in our blog post last week, we are cooperating with these investigations in Russian interference in the 2016 election,” a Twitter spokeswoman said in a statement. “Twitter deeply respects the integrity of the election process, and will continue to both work with the investigations and to share details of our findings with the public as we are able."

Google is yet to release any information about Russia-backed profiles producing content on its platforms or purchasing advertisements, though the search giant is investigating such activity.