Vice President Dick Cheney on Friday vigorously defended a secret program that examines banking records of Americans and others in a vast international database, and harshly criticized the news media for disclosing an operation he said was legal and "absolutely essential" to fighting terrorism.

"What I find most disturbing about these stories is the fact that some of the news media take it upon themselves to disclose vital national security programs, thereby making it more difficult for us to prevent future attacks against the American people," Mr. Cheney said, in impromptu remarks at a fund-raising luncheon for a Republican Congressional candidate in Chicago. "That offends me."

The financial tracking program was disclosed Thursday by The New York Times and other news organizations. American officials had expressed concerns that the Brussels banking consortium that provides access to the database might withdraw from the program if its role were disclosed, particularly in light of anti-American sentiment in some parts of Europe.

But the consortium, the Society for Worldwide Interbank Financial Telecommunication, or Swift, published a statement on its Web site on Friday, saying its executives "have done their utmost to get the right balance in fulfilling their obligations to the authorities in a manner protective of the interests of the company and its members."

A representative for the cooperative, speaking on condition of anonymity because he was not allowed to talk about its internal discussions, said that he knew of no discussions about withdrawing, adding that the group was "very resolute" in its commitment to the financial tracking operation.

The program, run out of the Central Intelligence Agency and overseen by the Treasury Department, has allowed counterterrorism authorities to gain access to millions of records of transactions routed through Swift from individual banks and financial institutions around the world. The data is obtained using broad administrative subpoenas, not court warrants.

Investigators have used the data to do "at least tens of thousands, maybe hundreds of thousands of searches" of people and institutions suspected of having ties to terrorists, Stuart Levey, an under secretary at the Treasury Department, told reporters at a briefing on Friday. Officials say the program has proven valuable in a number of foreign and domestic terrorism investigations, and led to the 2003 capture of the most wanted Qaeda fugitive in Southeast Asia, known as Hambali.

News accounts of the program appeared just as President Bush returned from a two-day trip to Europe, where he met in Vienna with leaders of the European Union. Neither that organization nor any of its member states commented Friday, but one advocate for civil liberties in London said the program could create new tensions in Europe just as Mr. Bush was trying to smooth trans-Atlantic relations.

"Our data has been effectively hijacked by the U.S. under cover of secret agreements and entirely undisclosed terms," said the civil liberties advocate, Simon Davies, the director of Privacy International, a London-based organization focused on the intrusion on privacy by governments and businesses. "There will be a snapping point, and this may be it."

Initial reaction from global banks was muted, with one executive saying that while the privacy of information was a contentious issue within the industry, the Swift operation had so far generated few complaints.

In Washington on Friday, privacy groups and civil liberties advocates were critical of the program, as were some Democrats and one prominent Republican on Capitol Hill.

The executive director of the American Civil Liberties Union, Anthony D. Romero, condemned the program, calling it "another example of the Bush administration's abuse of power."

Lauren Weinstein, the head of the California-based Privacy Forum, an online discussion group, raised concerns about lack of independent review of the operation. "Oversight is the difference between something being reasonable and something being abuse," he said.

Senator Arlen Specter, Republican of Pennsylvania and chairman of the Senate Judiciary Committee, said he had sent letters on Friday to both Treasury Secretary John W. Snow and Attorney General Alberto R. Gonzales on the issue. While he declined to release the letters, he said he was concerned about the legal authority for the operation.

Mr. Specter has been at odds with the administration over another previously secret counterterrorism operation, the National Security Agency's domestic eavesdropping program. The senator said he was particularly troubled that the administration had expanded its Congressional briefings on the financial tracking program in recent weeks after having learned that The New York Times was making inquiries.

"Why does it take a newspaper investigation to get them to comply with the law?" the senator asked. "That's a big, important point."

In explaining the program, Mr. Levey, the Treasury under secretary who oversees the program, said in an interview earlier in the week that "people do not have a privacy interest in their international wire transactions." But Mr. Specter was skeptical.

"I'm not surprised that a Treasury official would take that position, but I'm not so sure he's right," the senator said. "I don't think it's an open-and-shut question."