The Supreme Court delivered a major blow to TikTok by declining to block a law that would likely lead to the social media platform being banned in the United States within days.

WASHINGTON — The Supreme Court on Friday unanimously upheld the federal law banning TikTok beginning Sunday unless it's sold by its China-based parent company, holding that the risk to national security posed by its ties to China overcomes concerns about limiting speech by the app or its 170 million users in the United States.