When a federal judge ruled two weeks ago that the American Civil Liberties Union could finally reveal the existence of a lawsuit challenging the USA Patriot Act, the group issued a news release.

But the next day, according to new documents released yesterday, the ACLU was forced to remove two paragraphs from the release posted on its Web site, after the Justice Department complained that the group had violated court secrecy rules.

One paragraph described the type of information that FBI agents could request under the law, while another merely listed the briefing schedule in the case, according to court documents and the original news release.

The dispute set off a furious round of court filings in a case that serves as both a challenge to, and an illustration of, the far-reaching power of the Patriot Act. Approved by Congress in the wake of the Sept. 11, 2001, attacks, the law gives the government greater latitude and secrecy in counterterrorism investigations and includes a provision allowing the FBI to secretly demand customer records from Internet providers and other businesses without a court order.

The ACLU first filed its lawsuit challenging the constitutionality of such demands, known as national security letters, on April 6, but the secrecy rules of the Patriot Act required the challenge to be filed under seal. A ruling April 28 allowed the release of a heavily censored version of the complaint, but the ACLU is still forbidden from revealing many details of the case, including the identity of another plaintiff who has joined in the lawsuit. The law forbids targets of national security letters to disclose that they have received one.

ACLU lawyer Ann Beeson said the court order also means that she "cannot confirm or deny" whether the ACLU is representing the second plaintiff. The group is the only counsel listed in court documents.

The dispute over the ACLU's April 28 news release centered on two paragraphs. The first laid out the court's schedule for receiving legal briefs and noted the name of the New York-based judge in the case, U.S. District Judge Victor Marrero.

The second paragraph read: "The provision under challenge allows an FBI agent to write a letter demanding the disclosure of the name, screen names, addresses, e-mail header information, and other sensitive information held by 'electronic communication service providers.' "

Justice lawyers said that both paragraphs violated a secrecy order and that the ACLU should be required to seek an exemption to publicize the information, court records show. Justice spokesman Charles Miller declined to comment yesterday.

"It simply never occurred to us that this information would be covered by the sealing order, because it's completely non-sensitive, generic information," Beeson said.

The dispute was partly resolved yesterday. Marrero ruled that the briefing schedule could be publicized, along with edited versions of other court filings. But the paragraph describing the information that can be sought remains absent.