ByteDance declined to comment. The sources declined to be named as the information is not public.

TikTok had come under pressure from the Trump administration in the United States to divest the app's U.S. operations over concerns that user data could be passed on to China, which TikTok has repeatedly denied.

Reuters reported last year that TikTok had moved its key research capabilities outside China and had approached employees from tech giants like Google for a senior engineering role.

U.S. investors, including Oracle Corp and Walmart Inc, have discussed with ByteDance taking a majority stake in TikTok's American operations.

The White House under Biden has said it is keeping risks TikTok may present to U.S. data under review, but stressed it has taken no new "proactive step" relating to the pending TikTok deal, Reuters reported earlier this month.

"With Trump now out of office, and the new Biden administration focused on urgent matters like the pandemic and the economy, I think TikTok has more leeway to make strategic, rather than reactive, decisions," said Mark Natkin, managing director of technology consulting firm Marbridge Consulting.

Kevin Chen, a former Didi Chuxing executive who recently joined ByteDance, will replace Zhu as Toutiao's new CEO, the sources said, adding that the personnel changes have not been internally announced and are still subject to change.

Zhu, now based in Beijing, joined ByteDance in 2015 and became Toutiao's CEO in 2019. Prior to ByteDance, he worked as an architect at China's search engine giant Baidu.

In September, Reuters reported that ByteDance planned to invest billions of dollars and recruit hundreds of employees for its new Southeast Asia regional headquarters in Singapore.

(Reporting by Yingzhi Yang in Beijing and Brenda Goh in Shanghai; Editing by Jan Harvey and Stephen Coates)

By Yingzhi Yang and Brenda Goh