The CEO of TikTok Kevin Mayer resigned from his post on Thursday, amid pressure from the Trump administration for the Chinese-owned video-sharing app to sell its business.
The White House has said the app, which is owned by ByteDance, is a threat to US national security.
The “political environment has sharply changed” since he took over the position in May, Mayer wrote in a letter to employees explaining his decision to leave.
US President Donald Trump in July moved to ban the app in the US, unless parent company ByteDance sells its US operations to an American company by mid-September.
“I have done significant reflection on what the corporate structural changes will require, and what it means for the global role I signed up for,” wrote Mayer, a former Disney executive who joined TikTok before the recent trade quarrel between the US and China.