(Kacper Pempel/Reuters)

Twitter is banning two Russian government-affiliated news sites from advertising on its platform, the social network said Thursday.

Twitter said its decision to block advertising from the sites stemmed from the conclusion of the U.S. national intelligence report in January that said that the Kremlin used the sites Russia Today (RT) and Sputnik, along with a far-flung network of “quasi-government trolls,” to interfere in the 2016 U.S. presidential election.

We did not come to this decision lightly, and are taking this step now as part of our ongoing commitment to help protect the integrity of the user experience on Twitter,” the company said in a blog post.

Twitter's move may put some pressure on Google and Facebook to pull similar advertising from their sites. RT’s YouTube channel has more than 2 million followers and claims to be the “most watched news network” on the video site. Its Facebook page, which has an accompanying video channel, has more than 4 million likes and followers. Twitter has said that accounts from RT and Sputnik may continue to tweet but now may not advertise.

RT responded to Twitter’s decision in a blog post, saying that it had never violated any advertising rules on Twitter, used any bots or deliberately spread disinformation.

The news agency also highlighted Twitter’s role in helping RT spread its messages on the platform. RT said that it even published a marketing proposal Twitter had sent the company last year in which it tried to sell RT on its services, including Twitter’s ability to help RT “deliver an unbiased point of view of the U.S. elections with an edge.”

In a story on the company's site, Sputnik's editor-in-chief Margarita Simonyan called Twitter's decision "regrettable."

In an emailed statement, Sputnik disputed that it had ever used advertising. "Sputnik has never used paid ads for promotion on Twitter," said the company's communications director Beverly Hunt. "Sputnik news channels are followed by people who are tired of the mainstream media and who are looking for a fresh perspective on the news."

Twitter and other Silicon Valley companies are facing government scrutiny over the role they played in allowing Russian disinformation to spread on their platforms during the election. Twitter has since taken some steps toward transparency, announcing earlier this week that it would make all advertising public. Facebook made a similar announcement several weeks ago.

Lawyers from the company are scheduled to testify before Congress on Nov. 1. They are facing potential new regulation over the disclosure of political advertising online.

Twitter said Thursday that it was taking $1.9 million that the company projected that it had earned from RT advertising since 2011, including $274,000 spent during the U.S. election, and donating the funds to external research into the use of Twitter in civic engagement and elections, including malicious automation.

Critics have said that the focus on advertising by Silicon Valley companies is misguided because far more disinformation was spread through free posts, tweets, videos and other content. The companies have not disclosed any information publicly about the reach of those organic posts.