A US judge has blocked the Trump government's attempt to ban the Chinese messaging and payments app, WeChat. A group of US WeChat users had challenged President Donald Trump's executive order that sought to shut WeChat down in the country. The court said the ban raised serious questions related to the constitution's first amendment, guaranteeing free speech. The Department of Commerce had announced a bar on WeChat appearing in US app stores from Sunday, effectively shutting it down. The Trump administration has alleged it threatens national security. Both WeChat and China have strongly denied the claim.