A federal judge in California on Sunday blocked the Trump administration's executive order banning downloads of the Chinese-owned messaging app, WeChat.

In her decision, the judge said the plaintiffs - a group of U.S.-based WeChat users - had raised serious questions about whether the order threatened their First Amendment rights, and that a ban would place significant hardship on the 19 million people who use the app daily in the U.S.

Citing national security issues, the Commerce Department on Friday had issued restrictions against WeChat, owned by Chinese tech giant, Tencent.