A group of U.S. lawmakers is seeking to block a Pentagon program aimed at identifying potential terrorists in the United States by establishing an information database on Americans.

The Defense Advanced Research Project Agency in the Pentagon is to create the huge database that intelligence and law enforcement agencies could use in tracking terrorism suspects.

Critics, including Senator Russ Feingold, a Wisconsin Democrat, say the program would allow the Pentagon to collect and analyze personal information, which could be open to abuse.

"This unchecked system is a dangerous step that I think threatens some of the very freedoms that we are fighting to preserve in our fight against terrorism," he said.

Senator Ron Wyden, an Oregon Democrat, introduced legislation this week that would cut off funding for the project until Congress conducts a review.

"Our country must fight terrorists," he said. "But America should not unleash virtual bloodhounds to sniff into the financial, educational, travel and medical records of millions of Americans."

Some Republicans, including Senator Chuck Grassley of Iowa, have also expressed concern about the program, as have civil liberties groups.

"Privacy is about security," said Katie Corrigan, who is with the American Civil Liberties Union. "It is about the security of our family's most personal information medical records, financial information, sensitive files that used to be kept in our desk drawers at home are now out in public data bases. Total Information Awareness would exploit that fact, turning the power of the information age onto innocent people inside the United States."

Pentagon officials defend the program, saying it would help determine the feasibility of searching vast amounts of data to determine links and patterns suggestive of terrorist activities.