TikTok CEO Kevin Mayer has left the Chinese-owned video app firm just three months since joining, and only days since the company sued the administration of U.S. President Donald Trump over an executive order effectively banning it in the United States.

He will be replaced by U.S. General Manager Vanessa Pappas on an interim basis, TikTok said in a statement.

The resignation comes at a tricky time for super-fast growing TikTok as it tries to persuade both the United States and India that it is not a security threat, while at the same time holding discussions with prospective buyers following a second U.S. order demanding the sale of its U.S. operations.

Mayer was Walt Disney Co’s (DIS.N) top streaming executive before becoming chief executive officer of TikTok and chief operating officer of parent ByteDance on June 1.