ByteDance Ltd, the owner of popular short-video app TikTok and its Chinese sister-app, Douyin, said Thursday that founder and global chief executive, Zhang Yiming, would step down as CEO to focus on long-term strategy, according to a Wall Street Journal report. Co-founder, Liang Rubo, will take his place.

Zhang’s departure comes at a time of increasing regulatory pressure on Chinese tech companies, and following a year of uncertainty about TikTok’s future in the US market. In April, Shou Zi Chew, ByteDance’s chief financial officer, was named CEO of TikTok.

“I believe I can best challenge the limits of what the company can achieve over the next decade, and drive innovation, by drawing on my strengths of highly-focused learning, systematic thought, and a willingness to attempt new things,” Zhang said in a letter to employees on Thursday, which was also shared online by the company.