A US federal appeals court has ruled that prosecutors can demand Twitter account information of certain users in their criminal probe into the disclosure of classified documents on WikiLeaks.

The three-judge panel of the 4th US Circuit Court of Appeals also said the government's reasons as to why it is seeking the information can remain sealed.

The case involves three Twitter account holders with some connection to the secret-busting WikiLeaks website. They had argued that forcing Twitter to cooperate with the investigation by turning over data amounts to an invasion of privacy and has a chilling effect on the free speech rights of Twitter users.

The federal panel in Richmond rejected their appeal and affirmed a magistrate's court order that Twitter must turn over limited account information to prosecutors. The court said it weighed the right of public access against the need to keep an investigation secret. The appeals court agreed with the magistrate that the government's interest in keeping the documents secret outweigh the right to public access.

Prosecutors have said federal law specifically allows them to seek account information as a routine investigative tool. Specifically, the Stored Communications Act allows them to obtain certain electronic data without a search warrant or a demonstration of probable cause. The government must only show that it has a reasonable belief that the records it seeks are relevant to an ongoing criminal investigation.

"This is essentially a reasonable suspicion standard," the court wrote.

Under the Stored Communications Act, the government can also keep sealed documents related to their investigation from the subscribers. The appeals panel concluded the subscribers had no First Amendment right to access the documents. Prosecutors submitted their rationale for seeking the Twitter information to US Magistrate Judge Theresa Carroll Buchanan but it was kept secret and sealed also.

The court wrote that the "government's interests in maintaining secrecy of its investigation, preventing potential subjects from being tipped off, or altering behaviour to thwart the government's ongoing investigation, outweighed" the subscribers' claims.

The American Civil Liberties Union and the Electronic Frontier Foundation, representing the Twitter users, said the government can use those IP addresses as a sort of virtual tracking device to identify a specific computer used by an account holder and with it the user's physical location.

The appeals panel also allows the government to keep secret any similar orders it sought from other social media sites.