A US judge has blocked a government attempt to ban messaging and payments app, WeChat.
US Magistrate Judge Laurel Beeler said the ban raised critical questions related to the first amendment, guaranteeing free speech.
On Friday, the US commerce department issued an order citing national security grounds to block the app from US app stores owned by Tencent Holdings.
Both WeChat and China have strongly denied the claim. Tencent, the conglomerate that owns WeChat, had previously described the US ban as "unfortunate".
WeChat is an all-in-one mobile app that combines services similar to Facebook, WhatsApp, Instagram and Venmo.
Beeler’s preliminary injunction also blocked the commerce order that would have barred other transactions with WeChat in the US and degraded the site’s usability for current US users or potentially made it unusable.
The US Justice Department argued that blocking the executive order would "frustrate and displace the president's determination of how best to address threats to national security".
The ruling comes just after the TikTok deal, which will see US firms Oracle and Walmart allow them to keep operating.
WeChat has an average of 19 million daily active users in the US, analytics firms Apptopia said in August. It is popular among Chinese students, Americans living in China and some Americans who have personal or business relationships in China.
In her 22-page order, Beeler said that the government’s overarching national-security interest is significant. But on this record – while the government has established that China’s activities raise significant national security concerns – it has put in scant little evidence that its effective ban of WeChat for all US users addresses those concerns.
Michael Bien, a lawyer for the users, said: “The United States has never shut down a major platform for communications, not even during war times. There are serious first amendment problems with the WeChat ban, which targets the Chinese American community.”
WeChat was set up in 2011 and has been downloaded a total of 22 million times in the United States since January 2014.It is a multi-purpose app allowing users to send messages, make mobile payments and use local services. It has been described as an "app for everything" in China and has more than one billion monthly users.
Meanwhile, analysts and experts have questioned whether US officials will force Apple (AAPL) to remove WeChat and Weixin from its Chinese app store. A move like this would be a big blow to Apple and other US companies operating in China, where Weixin has become a daily necessity for hundreds of millions of people who use it to pay for goods and bills, among other items.