An Icelandic MP who once worked with Wikileaks says US officials have subpoenaed her personal details from the social networking website Twitter.
Birgitta Jonsdottir says the US Department of Justice also asked Twitter for all of her tweets since November 2009.
She says she has 10 days to appeal against the subpoena.
US officials have not commented on her claims, which have not been independently verified.
Ms Jonsdottir said on her Twitter feed: "USA government wants to know about all my tweets and more since 1 November 2009. Do they realise I am a member of parliament in Iceland?"
She said that she would call Iceland's justice minister to discuss the request.
"I think I am being given a message, almost like someone breathing in a phone," she said.
Ms Jonsdottir has said she helped to produce a video for Wikileaks showing a US Apache helicopter shooting civilians in Iraq in 2007.
The classified video, released by Wikileaks last April, brought the whistle-blowing website to the world's attention.
The site later released hundreds of thousands of classified and secret documents relating to the wars in Afghanistan and Iraq.
It also published cables sent by US diplomats across the world, deeply embarrassing the US authorities.
The website's founder, Julian Assange, is currently fighting extradition from the UK to Sweden, where he is wanted for questioning as part of an inquiry into alleged sex offences.
Ms Jonsdottir reportedly left Wikileaks late last year after she argued unsuccessfully that Mr Assange should take a low-profile role until his legal troubles were resolved.