WASHINGTON -- Attorney General Alberto Gonzales told lawmakers Thursday that warrantless spying on purely domestic phone calls between Americans on U.S. soil is an option in the war against terror.

"I'm not going to rule it out," he said in a hearing before the House Judiciary Committee.

The testimony caused alarm among some lawmakers.

"How can you not rule that out?" Rep. Jeff Flake, R-Ariz., said later. "I think it's a stretch to assume we gave them the authority" to conduct warrantless surveillance of international phone calls. But it's unreasonable, he said, "that they would feel they have the authority to do domestic surveillance."

Rep. Adam Schiff, D-Calif., called Gonzales' testimony a "shocking admission" that shows the administration "doesn't feel there is any limit to what they can do" under the 2001 congressional resolution authorizing military force.

Gonzales' comments came as lawmakers continued criticism of President George W. Bush's October 2001 decision to authorize the National Security Agency to eavesdrop on international phone calls and e-mails of Americans in the United States without first getting warrants from a secret intelligence court.

Critics have said that program violates the Fourth Amendment's requirement for reasonable searches and the Foreign Intelligence Surveillance Act of 1978, which requires the secret court to approve surveillance of U.S. citizens.

Bush and other administration officials have defended the decision to bypass the court, arguing that the president has power to authorize the surveillance as part of his inherent constitutional powers as commander-in-chief and by a congressional resolution passed after the 2001 attacks that authorized the use of military force.

Gonzales wouldn't answer questions about who reviewed the surveillance program before Bush authorized it, saying the information was classified.

"Mr. Attorney General, how can we discharge our oversight responsibilities if every time we ask a pointed question, we're told that the answer is classified?" said Rep. F. James Sensenbrenner Jr., R-Wis.

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