Encrypted messaging app Signal appears to be blocked in China alongside Jack Ma's Alibaba browser, as Beijing cracks down on social-media platforms

• China has reportedly blocked Signal and an Alibaba browser as it cracks down on social-media apps.
• Signal users in China couldn't send messages on the app from Monday evening.
• Alibaba's browser was pulled on Tuesday after the group was accused of misleading advertising.

Signal, a messaging app that rivals WhatsApp, and a internet browser made by Jack Ma's Alibaba appear to have been blocked in China, as Beijing continues to crack down on tech firms and social media sites.

Signal users in China reported on other platforms that they had difficulties working the app from Monday evening, including not being able to send messages, the Washington Post reported.

Despite this, users can still access Signal via a virtual private network (VPN), which hides users' locations.

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"Signal has been walled," users wrote on the Chinese microblogging site Weibo, the Post reported.

The app is still available for download via Apple's China App Store, CNBC reported, but it's unclear whether it will remain on the site for much longer.

Signal didn't immediately respond to Insider's request for comment.

The free messaging app offers end-to-end encryption, making it very difficult for third parties, including authorities, to see messages sent on the app. Signal is popular among tech giants, cybersecurity experts, journalists, and government officials.

Its popularity soared in January after WhatsApp sent users into a panic with an update to its terms and conditions.

Alibaba UC Browser pulled from app stores

Ecommerce group Alibaba had its internet browser pulled from Chinese app stores on Tuesday, the Financial Times first reported. Chinese authorities accused group's UC Browser of promoting misleading online ads that directed patients to private hospitals instead of public ones.

App stores operated by Chinese tech companies including Huawei, Xiaomi, and Tencent have blocked downloads or removed the browser, the FT reported.

It's the latest hit to Alibaba's founder, Jack Ma. Last year, Chinese authorities halted a $37 billion initial public offering of Ant Group, Alibaba's fintech affiliate.

Buzzy social media app Clubhouse was also blocked in China on February 8, after people flocked to it to discuss political and sensitive topics, such as Xinjiang's Uighur detention camps. Clubhouse conversations aren't recorded, making them difficult to monitor, and access is available by invitation only.