In his speech Thursday at Georgetown University on free speech, Mark Zuckerberg briefly called out Facebook's young Chinese-owned competitor TikTok.

"While our services like WhatsApp are used by protesters and activists everywhere due to strong encryption and privacy protections, on TikTok, the Chinese app growing quickly around the world, mentions of these protests are censored, even in the U.S.," Zuckerberg said in reference to the ongoing protests in Hong Kong. "Is that the internet we want?"

TikTok, which is owned by Beijing-based ByteDance, is a mobile app on which users can share and easily edit short videos. The app uses a machine-learning algorithm to present content tailored to each user and has exploded in popularity across the U.S. Facebook considers TikTok a competitor, and the start-up has even opened an office close to Facebook's headquarters so it can poach employees.

TikTok has come under fire, however, for allegedly suppressing content that Beijing deems politically unfavorable, such as the protests in Hong Kong, as the Washington Post first reported. TikTok refutes these reports.

"The Chinese government does not request that TikTok censor content, and would not have jurisdiction regardless, as TikTok does not operate there," a TikTok spokesperson told CNBC in response to Zuckerberg's comments. "To be clear: We do not remove videos based on the presence of Hong Kong protest content."