Twitter has identified more than 1,000 additional accounts which it claims were used by the Kremlin to influence the US presidential election.
The accounts were discovered as part of Twitter’s internal investigation into propaganda efforts by an organisation alleged to have links to the Russian government known as the Internet Research Agency.
Almost 4,000 troll accounts were identified to have links to this company by Twitter, including the latest 1,000.
Twitter said that in the ten weeks prior to the November 2016 vote, those accounts posted a combined 175,993 tweets – approximately 8.4% of which were election-related.
Key evidence linking the Kremlin to social media troll accounts has not been made public, despite questions being raised of Twitter’s methodology in identifying them.
Twitter had previously identified 2,752 accounts to a US Congressional inquiry, but at least one of those accounts was later reinstated after it was found to belong to a US citizen rather than a Russian troll.
Twitter has declined to explain why this account was flagged as a troll account, but said in its most recent update “all but a few accounts, which were restored to legitimate users, remain suspended”.
In December, Twitter was slammed by the chair of a British parliamentary committee for its “completely inadequate” response to an inquiry into Russian interference in the Brexit referendum.
A declassified intelligence community assessment in the US said that “the likely financier of the so-called Internet Research Agency […] is a close Putin ally with ties to Russian intelligence.”
Russia has denied allegations it interfered with the US election.
Regarding the troll accounts, Twitter said it was emailing notifications to 677,775 people in the US who followed, retweeted or liked a Tweet from one of those accounts during the election period.
It added: “Our work on these issues will never be done, and we will continue in our efforts to protect Twitter against bad actors and networks of malicious automation and manipulation.”
Twitter has informed a British committee investigating similar attempts to influence the Brexit referendum that it had only identified expenditure by one Russian-linked account on its platform.
The account belonged to media channel RT (formerly Russia Today) which spent roughly $1,000 (£750) during the EU referendum advertising its coverage.
Russia Today, alongside Sputnik, has since been prohibited from advertising on Twitter, and the company said it would donate the combined $1.9m (£1.4m) that RT spent globally towards academic research into elections and civil engagement.
Also in December, Facebook claimed that only three Kremlin-linked accounts were found to have bought advertisements which could have influenced the Brexit referendum.
These accounts, which Facebook claimed are associated with the Internet Research Agency, spent $0.97 (72p) on advertisements.