"I feel disconnected. I feel cut off from the world and my community," one influencer remarked when the app was down.

Even if temporary, the unprecedented shutdown of TikTok will have an impact on U.S.-China relations, domestic politics, the social-media marketplace and millions of Americans who depend on the app.

"TikTok and ByteDance Ltd. apps are no longer available in the United States, and visitors to the United States might have limited access to features," Apple said.