Twitter said Friday that Russian meddling ahead of the 2016 presidential election was more widespread than it initially estimated and it pledged to let users of the service know if they were exposed to propaganda associated with a Kremlin-linked troll farm.
The social network said it had identified 3,814 accounts linked to the Internet Research Agency, which was the seat of the Russian propaganda effort. In October, Twitter executives testified in front of Congress that it had foundaffiliated with the election interference.
The IRA-linked accounts posted 175,993 tweets between Sept. 1 and Nov. 15, 2016, of which 8.4% were election related, according to Twitter. The social network said it had suspended almost all of the accounts for violating its terms of service and had provided Congress with their handles.
The acknowledgment comes as Twitter and other social networks face mounting criticism from Washington about the way their platforms were used by Russia in the run-up to the divisive election. Earlier this week, representatives oftold Congress the companies had learned important lessons during the presidential election and pledged more transparency going forward.
Carlos Monje, Twitter's public policy director, said Wednesday the company has created a task force to handle issues that come up during the midterm elections in November. The plans include verifying the accounts of major party candidates to prevent copycats, working with federal and state election officials to monitor problems and improving its algorithm to eliminate fake accounts with election-related content.
The UK government has also requested that Facebook investigate whether Russia used it toahead of the country's vote on leaving the European Union, popularly known as Brexit.
Twitter also said it found 13,512 Russian-related automated accounts known as bots -- software that poses as real users -- in addition to the more than 36,000 accounts they previously revealed. The automated accounts represented two one-hundredths of a percent of all Twitter accounts at the time, the company said.
Twitter had previously said automated accounts were responsible for 1.4 million election-related tweets that received 288 million views.
Twitter said it will email 677,775 users in the US who liked or retweeted messages from Russian-linked accounts to let them know the accounts had spread misinformation or divisive messages. In the blog post, Twitter said the messages were no longer visible because the accounts had been suspended.
Virginia Sen. Mark Warner, the top Democrat on the Senate Intelligence Committee for more transparency, tweeted Friday that he was encouraged to see Twitter take a more proactive approach. He has been among the most vocal politicians to call on tech companies to be more transparent.
iHate: CNET looks at how intolerance is taking over the internet.
Batteries Not Included: The CNET team reminds us why tech is cool.
First published Jan. 18 at 3:31 p.m. PT.
Update at 3:58 p.m. PT: Adds more information on Twitter's investigation and reaction from Sen. Mark Warner.
Update at 4:32 p.m. PT: Adds more background.