Sen. Ron Johnson and several of his GOP colleagues are demanding answers from President Joe Biden regarding the White House's admission that the administration is collaborating with social media companies to "flag" Americans' posts for disinformation.

"Big Tech has now become Big Brother," Johnson, R-Wis., told FOX Business exclusively. "It’s the Big Brother arm of big government and it should concern and frighten every American."

White House press secretary Jen Psaki said during a press briefing earlier this month that Biden administration officials are coordinating with Big Tech firms and that the surgeon general's office had upped its research and tracking of disinformation.

"We're flagging problematic posts for Facebook that spread disinformation," Psaki said at the time.

The admission drew criticism from First Amendment advocates.

"It is outrageous the Biden administration is coordinating with Big Tech to infringe on American citizens’ First Amendment freedoms," Johnson told FOX Business. "This is a dangerous assault on freedom of speech and Big Tech, the mainstream media and the administration have no credibility in determining what is and isn’t misinformation."

Psaki said the administration was working with doctors and other medical experts to target false information about the COVID-19 pandemic specifically.

In a letter to the president obtained by FOX Business, Johnson was joined by Sens. Mike Lee, R-Utah, Rand Paul, R-Ky., and six more GOP members in expressing "deep concern" with the move.

The senators told the president in the letter, "We consider any efforts by the government to collude with social media in this manner to be a dangerous assault on Americans’ First Amendment right to freedom of speech."

"We want to reiterate that the Administration should halt any actions it has or is currently undertaking to censor Americans’ speech.," the letter reads. "Further, Congress and the American public must know how the Administration is carrying out this 'flagging' of American citizens’ speech."

The senators then listed a slate of requests for the administration to provide to Congress by Aug. 9, 2021, including, "The name, employing agency or office, and the job title of each individual in the executive branch carrying out ‘disinformation’ research and tracking of social media platforms." They also asked for all of the correspondence the administration has had with social media giants, a list of all the social media posts the administration determined should be flagged along with the justification, and how many taxpayer dollars have been spent on the Biden administration's endeavor to tamp down "disinformation."