Twitter and Reddit are cracking down on controversial content. Twitter will ban two Kremlin-backed news outlets and Reddit will ban forums for white supremacist groups, both companies announced last week.

Twitter said it is banning RT, formerly known as Russian Today, and Sputnik, from advertising on the platform. Both news outlets will be allowed to retain their Twitter accounts and followers.

"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 wrote in a blog post on Oct. 26. The social media company also disclosed that it had earned $1.9 million in advertising revenue from RT since 2011 and said it would donate that money to research fake news and the civil impact of Twitter.

Over the weekend, Twitter also permanently banned political operative Roger Stone over the weekend, according to Buzzfeed. Stone, a longtime ally of President Donald Trump, issued a series expletive-laden tweets insulting several CNN News anchors and contributors. He was suspended and later banned from the platform. 

Meanwhile, Reddit said it implemented a new policy that would ban content that incites violence. Some of the first forums to be blocked were ones for Nazi, racist, and white supremacist groups. "Going forward, we will take action against any content that encourages, glorifies, incites, or calls for violence or physical harm against an individual or a group of people," the company wrote in statement on Thursday.

The announcements were made less than a week before Twitter and other tech giants like Google and Facebook are scheduled to testify before the Senate and House Intelligence Committee about Russia's role in the 2016 presidential election. Twitter refined its transparency policies ahead of the hearing by announcing that it will mark political ads on the service and show users who purchased the ads.