At a Senate commerce committee hearing on social media algorithms today, Sen. Ron Johnson (R-WI) took the opportunity to take Facebook-owned Instagram to task for apparent bias in its suggested follows feature, which recommends new accounts for users to follow.

Sen. Johnson noted that when his staffers followed the Instagram page of the news website Politico, Instagram immediately suggested a range of liberal Instagram accounts to follow, despite the fact that they were conservatives.

According to the senator, Instagram recommended that his conservative staffers follow (among others) Bernie Sanders, Elizabeth Warren, Kamala Harris, Nancy Pelosi, HuffPost, The Daily Show, Hillary Clinton, Bill Maher, MoveOn.org and the Southern Poverty Law Center (SPLC).

Sen. Johnson asked the big tech representatives why his staffers saw no recommendations for conservative sources like Breitbart News, Newsmax, Fox News or Donald Trump.

The senator suggested that the list of suggestions may be because of Instagram’s liberal bias. Commerce Committee chairman Sen. John Thune (R-SD) noted that if search results and recommendations were based on “neutral algorithms” and artificial intelligence, based on big tech’s data on the behavior patterns of users, then conservative users would not see as many left-leaning and liberal sources as they do.

Facebook’s representative at the hearing could not provide a conclusive answer to Sen. Johnson, stating that they would need to see the user’s click pattern to explain the list of recommended follows. Other panelists suggested that the recommendations may have happened because the liberal accounts were in the news, or were simply more popular across Instagram.

Accusations of Instagram’s liberal bias have also been made by the president’s son, Donald Trump Jr., whose Instagram followers say the platform has been blocking them from liking posts and automatically unfollowing conservatives. Earlier this year, Instagram also deleted a post from Don Jr. about Jussie Smollett, later claiming that this decision had been made in error.

Breitbart News has reached out to Facebook, which owns Instagram, for comment.

Are you an insider at Instagram, Facebook or any other corporation who wants to confidentially reveal wrongdoing or political bias at your company? Reach out to Allum Bokhari at his his secure email address allumbokhari@protonmail.com.

Allum Bokhari is the senior technology correspondent at Breitbart News.