The company's other products for markets outside China will not be affected, Kuaishou said in a statement. "Our strategy for the international markets remains unchanged," it said,without providing a reason for Zynn's shutdown.

Apart from Zynn, for markets outside China, Kuaishou operates Kwai, which is mainly popular in South America, and Snack Video.

A reward system that offers users cash or gifts for signing up and referring friends helped Zynn to top U.S. app download charts last year.

The Tencent-backed short video apps developer also operates the Kuaishou app and competes with ByteDance's Douyin for the Chinese market.

(Reporting by Yingzhi Yang and Brenda Goh; Editing by Jacqueline Wong and Barbara Lewis)