Sen. Ted Cruz, a Republican from Texas, slammed Facebook CEO Mark Zuckerberg during his Congressional testimony on Tuesday, accusing the social media platform of being politically biased.

'There are a great many Americans who I think are deeply concerned that Facebook and other tech companies are engaged in a pervasive pattern of bias and political censorship,' Cruz said. 'There have been numerous instances with Facebook.'

One such example that the Texas Republican and former GOP presidential candidate cited had to do with the Trump-supporting sisters, Diamond and Silk.

Sen. Ted Cruz slammed Facebook for its perceived political bias against conservatives and asked Facebook CEO Mark Zuckerberg about it on Tuesday

Sen. Ted Cruz pointed out several instances to Mark Zuckerberg (pictured) in which he believed Facebook had displayed overt political bias

Sen. Ted Cruz pointed out a recent incident involving Facebook and Trump supporters Diamond and Silk

Diamond and Silk, who campaigned alongside Trump in 2016, had Facebook slow down the reach of their popular videos in which the women push pro-Trump messages.

'The policy team has come to the conclusion that your content and your brand has been determined unsafe to the community,' an email from Facebook read, according to the Washington Post. 'This decision is final and it is non appeal-able in any way.'

Facebook has since acknowledged sending the message, but said its contents were 'inaccurate.'

'We have communicated directly with Diamond And Silk about this issue. The message they received last week was inaccurate and not reflective of the way we communicate with our community and the people who run Pages on our platform,' Facebook's spokeswoman Sarah Pollack said. 'We have provided them with more information about our policies and the tools that are applicable to their Page and look forward to the opportunity to speak with them.'

Cruz's criticism went beyond this recent incident, as he cited a Gizmodo article that said that Facebook had routinely suppressed conservative stories from its trending news section, including articles on the Conservative Political Action Conference, Mitt Romney, the Lois Lerner scandal and Glenn Beck.

Facebook, Cruz charged, 'initially shut down the Chick-fil-A Appreciation Day page,' as well as a post from a Fox News reporter, along with some Catholic pages.

'To a great many Americans that appears to be a pervasive pattern of political bias,' Cruz said. 'Do you agree with that assessment?'

Zuckerberg responded by acknowledging that Silicon Valley, located in bright blue California, is an 'extremely left-leaning place.'

However, adding to the list of things he wanted to improve, the Facebook CEO told the senator that one of his priorities was making sure 'we don't have any bias in the work that we do.'