A US service provider is fighting government demands for it to hand over details of millions of activists.
The Department of Justice (DoJ) wants all visitors' IP addresses - some 1.3 million - to a website that helped organise a protest on the day of President Trump's inauguration.
DreamHost is currently refusing to comply with the request and is due in court later this month.
The DoJ has not yet responded to requests for comment from the BBC.
It is unclear why it wants the internet protocol addresses of visitors to website disruptj20.org, which organised a protest against President Trump on 20 January - the day of his inauguration.
"The website was used in the development, planning, advertisement and organisation of a violent riot that occurred in Washington DC on January 20, 2017," it wrote in its motion to the Superior Court of the District of Columbia, which sought to compel DreamHost to hand over the information.
It suggested that "a particular customer" was the subject of the warrant, but does not explain why it needed so much information on other visitors.
In a blog post on the issue, DreamHost said that, like many other online service providers, it was regularly approached by law enforcement about customers who may be the subject of criminal investigations.
But, it added, it took issue with this particular search warrant "for being a highly untargeted demand".
In addition to the IP addresses, DreamHost said that the DoJ requested the contact information, email content and photos of "thousands of visitors".
Civil liberties group The Electronic Frontier Foundation, which is helping DreamHost fight its case, said: "No plausible explanation exists for a search warrant of this breadth, other than to cast a digital dragnet as broadly as possible."
A hearing on the issue is due on 18 August.