The Trump campaign and the Republican National Committee sent a letter to Facebook's Mark Zuckerberg and Twitter's Jack Dorsey with complaints about how the social networks treat conservatives. 

Brad Parscale, Donald Trump's campaign manager for the US election in 2020, posted the letter to Twitter on Thursday, where it received hundreds of retweets within minutes. The letter requested information about Facebook's and Twitter's efforts to "prevent political bias" on their social networks. 

The letter was signed by Parscale and Ronna McDaniel, the chairwoman of the Republican National Committee.

"We recognize that Facebook and Twitter operate in liberal corporate cultures," the letter reads. "However, rampant political bias is inappropriate for a widely used public forum." 

The letter calls for an answer from the two companies by June 18. 

Twitter declined to comment. Facebook didn't respond to a request for comment. 

You can see the full letter here:

Conservatives have said that Facebook and Twitter are actively stifling their voices on social media, with politicians bringing it up to Zuckerberg on three separate occasions in public hearings. At a congressional hearing about Cambridge Analytica, Sen. Ted Cruz, a Republican from Texas who used the data analytics firm, spent his time asking about Diamond and Silk, two Trump-supporting personalities on Facebook. So did at least five other US lawmakers. 

At the European Parliament hearing on Tuesday, the UK's representative, Nigel Farage, did the same, accusing Facebook's algorithm of censoring conservatives. 

The letter on Thursday also pointed to Twitter deleting followers from popular conservative accounts. While people were outraged they'd lost thousands of followers, Twitter said the mass deletion was not political, pointing out that it was deleting fake bot accounts. 

While the letter complains about Facebook and Twitter censoring conservative viewpoints, the social network's critics have also credited social media for their success. 

Parscale told CBS' 60 Minutes that Facebook helped Trump win the White House, while Trump has transformed how world leaders use Twitter. In fact, a federal judge on Wednesday ruled the president can't block Twitter users who are critical of his policies from following him on the social network. 

In Farage's opening remarks to Zuckerberg, he told the Facebook CEO, "it's true that through Facebook and other forms of social media, there is no way that Brexit or Trump or the Italian elections could ever possibly have happened." 

The letter also calls for details on Facebook's voter registration push. The RNC and Parscale want to know who Facebook is pushing the ads toward, with concerns that only Democratic voters would be urged to register.

First published May 24, 8:08 a.m. PT.
Update, 9:21 a.m.: To add Twitter's response.

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