Sen. Ted Cruz clearly rattled Facebook founder Mark Zuckerberg Tuesday by grilling him about Facebook’s well-documented censorship of conservatives.

WATCH:

Zuckerberg had a relatively easy time facing questioning during his Tuesday testimony in front of the Senate Judiciary and Commerce Committees until Cruz took over the helm.

Cruz noted the number of examples of Facebook censoring conservatives, including labeling conservative commentators Diamond and Silk as “unsafe,” hiding stories about the IRS targeting conservatives and blocking over two dozen 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 admitted that Facebook’s location in the highly-liberal Silicon Valley could concern conservative users, but assured Cruz that the platform tries to be unbiased.

“Are you aware of any ad or page that has been taken down from Planned Parenthood?” Cruz shot at the tech billionaire.

“Senator, I’m not,” Zuckerberg conceded. “But let me just — ”

“How about MoveOn.org?” Cruz continued.

“I’m not specifically aware of those,” Zuckerberg again admitted.

Cruz also pointed out that Zuckerberg is unaware of the political breakdown of his employees and the 15,000-20,000 people who police content for the site, leaving Zuckerberg struggling to explain why conservatives should not be worried that the social media site is apt to block their content.

Follow Amber on Twitter