Prosecutors probing leaks in an investigation of terrorism funding are not entitled to the telephone records of two New York Times reporters, a federal judge ruled yesterday.

Judge Robert Sweet’s 121-page opinion was a resounding victory for the newspaper in its efforts to protect the sources of journalists Judith Miller and Philip Shenon. The government had sought the phone records as part of a grand jury investigation aimed at determining how the reporters learned in advance of planned federal raids and asset seizures involving two Islamic charities, the Global Relief Foundation and the Holy Land Foundation.

Judge Sweet found that the reporters were entitled to a qualified privilege against the disclosure of their sources. The government did not meet its “heavy burden” of showing that the phone records were essential to the probe, the judge said.

“The court has balanced the interests of the free press and the government,” Judge Sweet wrote. “That balance requires maintaining the secrecy of the confidential sources.”

An attorney for the Times, Floyd Abrams, praised the decision. “It is a substantial vindication of the right of journalists to protect their sources,” he said in an interview.

The federal prosecutor on the case, Patrick Fitzgerald of Chicago, said an appeal was possible.

“We respectfully disagree with Judge Sweet’s decision and are considering our appellate options,” Mr. Fitzgerald said in a statement released by his office.

In his ruling, Judge Sweet noted that Mr. Fitzgerald maintained the government had “reasonably exhausted” other means of figuring out who leaked word of the December 14, 2001, raid on Global Relief, which was based in Illinois. However, the judge said the government had not demonstrated that it had made an exhaustive effort, including “whether it has interviewed all government employees with access to the ‘leaked’ information, whether it has examined the telephone records of all such employees, or what other steps it has taken that would avoid the need to engage in the contemplated invasion into the protected relationship between reporter and confidential source.”

The judge’s ruling yesterday appeared to be an express rejection of an opinion issued by a federal appeals court in Washington last week in a separate case that also involved the Times and Ms. Miller. The appeals court ruled that Ms. Miller and another journalist, Matthew Cooper of Time Magazine, had no privilege to resist subpoenas that ordered them to disclose confidential sources before a grand jury investigating the disclosure of the identity of a CIA agent, Valerie Plame.

Mr. Abrams said Judge Sweet’s decision “stands in sharp contrast” to the appeals court’s opinion in the Plame case. “He made clear that the 2nd Circuit has a different view of the matter,” Mr. Abrams said.

Judge Sweet pointed out that the 2nd Circuit Court of Appeals, which hears cases from New York, has recognized a qualified privilege for reporters in criminal trials. He said it was not clear why the same principle should not apply in a grand jury context.

The disagreement among the circuits involves the proper interpretation of a 1972 Supreme Court decision, Branzburg v. Hayes. The case, which involved a grand jury subpoena issued to a reporter, was decided by a vote of 5 to 4. While the journalist involved was ordered to testify, one of the justices in the majority, Lewis Powell, suggested the courts should provide some protection to keep reporters from being drawn into criminal investigations.

Mr. Abrams said Judge Sweet’s ruling will be prominently mentioned when the Times asks the full bench of the appeals court in Washington to reconsider last week’s ruling, which was issued by a three-judge panel. “It certainly is a case we will bring to that court’s attention,” he said.

One former prosecutor, Joseph DiGenova, predicted that Judge Sweet’s decision will be overturned. “It’s certainly wrong under Branzburg,” Mr. DiGenova said.

He insisted that the effort to obtain the phone records is actually more respectful of journalists’ prerogatives than trying to subpoena the reporters directly, although he doubted many reporters would share his view.

A law professor at the University of Minnesota, Jane Kirtley, said seizing phone records is more invasive than subpoenaing reporters because the phone records can show all of a journalist’s contacts for a period of weeks or months.

“It’s that scattershot approach. It does run the risk of sweeping up confidential and nonconfidential information that doesn’t relate to the investigation,” said Ms. Kirtley, who formerly headed the Reporters Committee for Freedom of the Press.

Several legal analysts said they do not expect the Supreme Court to address the issue anytime soon, despite the obvious split among the appeals courts.