Twitter is expected to provide evidence to Congress over alleged Russian trolls iStock

Social media platform Twitter is soon expected to join its rival Facebook in providing evidence to the US Congress regarding how its services may have been exploited by Russian trolls during the American presidential campaign in 2016, it has emerged.

Senator Mark Warner, the top Democrat sitting on the Senate Intelligence Committee, has said that revelations which came to light this week (6 September) – revealing state-backed trolls used Facebook advertising to sway public opinion – may be "the tip of the iceberg".

"[Facebook] had a fairly narrow search. I've been raising this issue for months. They have dismissed this issue for months," Warner said, first reported by The Hill.

"How extensive was the Russian involvement of using Facebook, Twitter and other social media forums?" he questioned, telling reporters on Thursday that "the American people deserve to know both the content and the source of information that is being used to try to affect their votes".

The politician claimed that a similar analysis from Twitter is now expected to be submitted.

A Twitter spokesperson did not immediately respond to a request for comment from IBTimes UK.

The storm kicked off following a report in The Washington Post which said Facebook officials had confirmed to Congress that, since 2015, up to $100,000 in total advertising had been traced to a Russian "troll farm" specialising in the spread pro-Kremlin talking points.

The same day, elaborating on the revelation, Facebook's chief security officer Alex Stamos wrote in a blog post affirming that some accounts were "likely operated out of Russia".

The ads, he said, focused on "amplifying divisive social and political messages across the ideological spectrum" including LGBTQ matters to gun control. About one quarter were geographically targeted and, of those, more were purchased in 2015 than last year.

After the US election last November, Facebook founder and chief executive Mark Zuckerberg said that "we gave tens of millions of people tools to share billions of posts and reactions about this election. A lot of that dialog may not have happened without Facebook".

He told a California technology conference at the time that it was "a pretty crazy idea" to suggest that Facebook helped spread misinformation and fake news.

The use of Russian troll farms was exposed in detail by an exposé in the New York Times back in June 2015, finding that people were being paid to "wreak havoc all around the internet".

During the election period, Twitter was swarmed by politically-charged 'bot' profiles.

The US government has launched a number of probes into alleged Russian interference in its democratic system. Its intelligence community – the NSA, FBI and CIA – believes the Kremlin ordered the clandestine social engineering operation in order to help elect Donald Trump.

In January 2017, it said that Moscow's use of hacks and leaks in the election was "unprecedented".

A declassified intelligence report concluded: "[The campaign] blends covert intelligence operations—such as cyber activity—with overt efforts by Russian government agencies, state-funded media, third-party intermediaries, and paid social media users or 'trolls.'"