Senator Mark Warner, whose panel is investigating alleged Russian interference in the election, said Twitter officials had not answered many questions about the Russian use of the platform and that it was still subject to foreign manipulation.
Social media company Twitter revealed that more than 200 of its user accounts were actually outlets for Russian-linked propaganda.
Twitter has identified and blocked 201 suspected Russian-linked accounts connected to the spreading of false information in last year's USA presidential election, the social network said Thursday.
Twitter added that it found another 179 associated accounts, but none was registered as an advertiser.
"Blacktivist" fake social media accounts have been tied to the Russian government, which used the handle on Facebook and Twitter in an attempt to raise racial tensions during the USA elections, CNN reported on Thursday, citing exclusive sources.
Twitter has blocked 201 accounts with suspected Russian links responsible for spreading fake news in the 2016 U.S. presidential election. The statement said RT, which was named in January in a U.S. intelligence report on election interference, spent at least $2,74,100 in 2016 for 1,823 tweet ads or "promotions" that "definitely or potentially targeted the USA market". Warner went on to say that Twitter's response is "deeply disappointing" and "frankly inadequate on nearly every level".
Warner in remarks to reporters called Twitter's statements "deeply disappointing" and "inadequate on nearly every level".
San Francisco: As the probe into Moscow's alleged meddling in the 2016 U.S. presidential election intensifies, Twitter announced that it has deleted over 200 fake Russian accounts and identified Russia Today of buying bought ads targeted at American users' accounts.
The Senate Intelligence Committee has asked representatives from each of the three tech titans to testify at an open hearing on November 1 involving Russia's role in the election, a Senate aide confirmed to Reuters on Wednesday.
Twitter pledged more transparency on what it is doing to take down bots and manipulative networks, saying, however, that there would be some components it could not publicly share.
Of the 450 accounts that Facebook released as part of its investigation, Twitter was able to match 22 of those to accounts on its own site. "This is an ongoing process and we will continue to collaborate with investigators", Twitter said in its statement.
Facebook Inc. and Google Inc. will join Twitter in further sessions with US intelligence committees in the coming months.
Twitter also briefed the House of Representatives Intelligence Committee on Thursday.
RT editor in chief Margarita Simonyan defended RT's purchase of advertisements on Twitter, seemingly seeking to distance RT from suggestions that it may be linked to state-supported social media campaigns aimed at manipulating public opinion in the West.