The Chinese communication app WeChat will initially remain available for US users.
A judge in California suspended the app's suspension imposed by the Washington Department of Commerce with a state-wide injunction.
The app should disappear from the download platforms in the USA on Monday and lose most of its functionality.
WeChat users had complained against this, invoking the right to freedom of expression.
The app is used by 19 million people in the US, primarily to keep in touch with relatives and friends in China.
The judge of the US magistrate, Laura Beeler, ruled against the actions of the US government after the users' complaint.
The lawsuit has raised "serious questions" about freedom of expression, she told tech
blog The Verge
She came to the conclusion that a temporary injunction is justified because WeChat would suffer too much damage from the sanctions, while the operator could still prevail in the main proceedings.
The background is a technology dispute between the USA and China.
US President Donald Trump suspects the Chinese video platform TikTok of espionage for China and asked the Chinese parent company Bytedance to sell the US branch of the video platform.
On Friday, the Department of Commerce in Washington announced that it would block TikTok and WeChat from being downloaded via the Google and Apple app marketplaces from Sunday.
The Ministry said the Chinese Communist Party had shown its intention to use these online services to "threaten national security, foreign policy and the economy of the United States."
The operator WeChat rejects this.
The lockdown on Tiktok was postponed for a week on Saturday after an agreement was reached to sell the US division to US companies Oracle and Walmart.
The sale still has to be approved by various bodies.