When Facebook, Google and Twitter testify before Congress later this week, the tech giants will reveal to investigators that the scope of the Russian campaign to spread disinformation and propaganda across the platforms was worse than what the companies originally stated, Recode reported.

Lawyers from the tech giants will sit before the House and Senate Intelligence committees in hearings held on October 31 and November 1 respectively, in which the companies will answer questions about their internal investigations into Russian activity intended to interfere with the 2016 United States presidential election.

According to Recode, Facebook found that about 126 million users in the U.S. may have been exposed to posts, stories and other content created by groups linked to the Russian government. Much of that content was intended to play upon hot-button political topics and spread false information to users. The information will be delivered by Colin Stretch, the general counsel of Facebook.

Google and Twitter will also provide more details about Russian activity on their platforms, including advertisements purchased by Russian government-backed groups and content created and spread by Russian trolls, with both companies expected to include new details about their investigations that have yet to be disclosed publicly.

Earlier this month it was reported by the New York Times that Google discovered accounts associated with the Russian government purchased about $4,700 worth of search advertisements and other display ads. The search giant also reportedly found another $53,000 worth of ads with political material that were purchased from Russian IP addresses with and paid for with Russian currency, though it it was not confirmed to be associated directly to the Russian government-backed efforts.

The Washington Post also reported that Google found 18 YouTube channels that were associated with Russian propaganda campaigns. A number of Gmail accounts linked to Russia were also apparently used to open accounts on other platforms.

Google has yet to publicly confirm any of the reporting but is expected to comment on its findings when the company’s director of law enforcement and information security Richard Salgado testifies.

Twitter is also likely to add more detail to Russian activity through the company’s acting general counsel Sean Edgett.

The social network revealed in September that it had found 22 accounts it believed to be connected to Russian trolls. Those account also led to another 179 related or linked accounts that may have also been involved in a russian campaign.

The company said it took action on those accounts which were found to be in violation of the social media platform’s rules. Twitter also insisted that none of these accounts were registered advertisers on the site.

Despite its early disclosures, Twitter has come under fire for a number of its actions regarding apparent Russian activity on the platform. The company let a Russian-run, far-right Twitter account with the handle @TEN_GOP to operate for nearly two years without being taken down despite numerous reports filed against the account.

Twitter also was criticized after the company revoked the advertiser status of Russian government-funded news organization Russia Today (RT) once it was revealed the company approached RT in advance of the 2016 U.S. presidential election with a multi-million dollar advertising proposal.

Facebook, Twitter and Google have all yet to respond to requests for comment on the reports.