Central Intelligence Agency (CIA) director William Burns on Friday warned that United States citizens should be "really careful" on TikTok.
Several federal agencies, including the White House, have banned Chinese-owned video-sharing platforms from government equipment.
Burns said he shared concerns expressed by other US officials that TikTok could pose a threat to the country's national security.
TikTok is a Chinese-owned platform that has come under intense scrutiny by US lawmakers.
The company has also been accused of censoring content that is politically sensitive to the Chinese government.
US lawmakers have been cracking down on Chinese companies amid national security fears.
the US Senate passed a bill to bar federal employees from using TikTok on government-owned device.