Access to US audio app Clubhouse was blocked in China on Monday, users and an anti-censorship watchdog said, ending a brief window that allowed thousands of mainland users to join in discussions often censored in China.

Launched in early 2020, Clubhouse's global user numbers soared earlier this month after Tesla CEO Elon Musk and Robinhood CEO Vlad Tenev held a surprise discussion on the platform.

Masses of new users joined from mainland China, taking part in discussions on topics that included sensitive issues such as Xinjiang detention...