WASHINGTON - The Obama administration, for a second straight day, frustrated Democratic lawmakers yesterday by declining to say whether it backed their demands for more civil-liberties safeguards in antiterrorism surveillance and property seizures.

Democrats on the Senate Judiciary Committee kept pressing Assistant Attorney General David Kris to go beyond previous administration statements that it supported continuing provisions of the USA Patriot Act that will expire at year's end.

"We don't have an official administration position" on any proposed legislation, Kris said.

Chairman Patrick J. Leahy (D., Vt.) had asked whether the administration would back his proposal to continue the expiring sections for four years with revisions and increase audits of the government's actions.

Sen. Richard J. Durbin (D., Ill.) sought a commitment to protect libraries from unreasonable requests for information on people using the facilities.

Sen. Dianne Feinstein (D., Calif.), chairwoman of the intelligence committee, asked: "Is there anything [in Leahy's bill] that would impede or affect" a current terrorism investigation in New York and Colorado?

"The cards are rather stacked" in favor of the government, Leahy said.

Kris responded: "We're willing to look to see if these tools can be sharpened."

Sen. Jeff Sessions of Alabama, the only Republican at the hearing, said he did not believe "there have been any abuses to date" of the Patriot Act. He said the law, originally enacted after the 9/11 attacks, gave the government the same powers in terrorism cases that it has to pursue drug dealers and mobsters.

Several Democrats in both chambers said they not only want to revise the expiring provisions but review the entire Patriot Act, to prevent what they contend were civil-liberties and privacy abuses by the Bush administration.

"This time around, we have the opportunity to get this right," said Sen. Russell D. Feingold (D., Wis.).

On Tuesday, another Justice Department official gave similar responses to the House Judiciary Committee. Liberal lawmakers dominating that panel expressed their dissatisfaction more sharply.