Federal prosecutors on Tuesday defended as routine their efforts to obtain information on the accounts of at least four Twitter users as part of a criminal investigation into the release of secret documents by the WikiLeaks website.

Lawyers for three of the account holders, including a member of Iceland's parliament, asked a federal magistrate to vacate an order she issued late last year requiring Twitter to turn over detailed information on the accounts in question. All of the account holders have some association with WikiLeaks.

The judge, Theresa Carroll Buchanan, did not rule on the lawyers' motions at Tuesday's hearing, and said she will instead issue a written ruling at a later date. Any ruling she issues can be appealed to a district court judge.

The trio's lawyers argued that the government is on a fishing expedition and that the information sought by the government amounts to an unconstitutional assault on their freedoms of speech and association. They said the information would essentially give the government round-the-clock knowledge of the account holders' whereabouts by allowing tracking of the computers used to send the tweets.

Assistant U.S. Attorney John Davis said the information sought by prosecutors is routine data that is turned over all the time in the course of criminal investigations, no different than phone records or credit card bills.

A specific federal law, the Stored Communications Act, allows the government to obtain certain records about electronic communications without a search warrant and without demonstrating probable cause.

"This is an investigative measure used in criminal investigations all over the country, every day," Davis said.

Davis said the government is seeking information on only four Twitter accounts, even though accounts associated with five different names were mentioned in the initial Dec. 14 court order — those of Assange; Pfc. Bradley Manning, the Army intelligence analyst suspected of supplying documents to WikiLeaks; and the three who filed the motions heard in Tuesday's hearing: Birgitta Jonsdottir, Rop Gonggrijp and Jacob Appelbaum. Jonsdottir is a member of Iceland's parliament.

Court documents indicate the government has informally narrowed its request and is no longer seeking records connected to any Twitter accounts associated with Manning, although under the order approved by Buchanan in December the government would be entitled to them.

The lawyers for the trio also asked a judge to unseal any orders that may have been issued to other social media websites, like Facebook.

"The public has an immense interest in having those documents unsealed," said Aiden Fine with the American Civil Liberties Union, citing the ongoing public debate over whether WikiLeaks and its founder, Julian Assange, should face criminal charges in the United States. WikiLeaks has released thousands of classified documents related to the wars in Iraq and Afghanistan, as well as diplomatic cables touching on U.S. relations with countries all over the world.

Assange did not participate in Tuesday's hearing, even though he is apparently a subject of the court order. WikiLeaks issued a press release Monday stating that Assange, an Australian, "claims that the American courts have no jurisdiction over him."

In the statement, Assange called the government's pursuit of the Twitter records "an outrageous attack by the Obama administration on the privacy and free speech rights of Twitter's customers."

Alan Dershowitz, an attorney serving as an adviser to Assange's lawyers in Great Britain, said he agrees that the government's efforts to obtain the Twitter records infringe on the users' constitutional rights.

In a phone interview, Dershowitz noted the role that social media has played in government protests in Egypt, Iran and elsewhere and those governments' attempts to crack down on social media use, and said the United States should set an example that allows social media communication without potential government intrusion.

"The government should have to show some credible basis ... before in fringing on associational rights," Dershowitz said.