The FBI was criticized for conducting surveillance on activists during a congressional hearing Tuesday called to consider a broad range of options that would increase the government's homeland security powers.

Two Democratic lawmakers on the House Homeland Security Committee said the FBI may have gone too far by monitoring people and groups across the country planning to protest at the Republican National Convention in New York from Aug. 30 to Sept. 2. The New York Times reported on the surveillance effort on Monday.

The hearing touched on a range of ideas for increasing security measures in response to the final report from the 9/11 commission, such as creating a networked system of databases that allows law enforcement officials to access broad information about people, and developing a national identification card for U.S. citizens. Lawmakers and witnesses alike expressed concern for preserving civil liberties while increasing security.

"What we do believe is that, as we try to protect ourselves, there is always the danger, as we get into these new methods of protection, that our civil liberties will be jeopardized," 9/11 commission Chairman Thomas Kean, former Republican governor of New Jersey, said during the hearing.

Rep. Sheila Jackson Lee, D-Texas, said activists who believe they are being intimidated by the FBI should contact members of Congress.

"Security is one thing, but intimidation and oppression is another thing," she said.

Rep Barney Frank, D-Mass., questioned whether directing FBI agents to monitor and interview people who plan to protest is a waste of federal resources.

"There is a troubling tendency here to take this option of pre-emption which, [it] seems to me, is controversial enough in the international area, and apply it domestically," he said. "Is the FBI that deep in extra agents that they've got people with nothing else to do for the summer than go out and do this?"

Maureen Baginski, the FBI's executive assistant director of intelligence, testified that the coming Republican convention and the Democratic National Convention last month were designated as national security special events.

"In accordance with that, every effort is made to ensure that any threat to the security of that event is taken care of within the confines of the Constitution and the law, as we always do," she said.

"There is absolutely no truth to the allegation that any of these things were taken outside of predication and outside the bounds of the Constitution," she added. "I understand the concerns of citizens, but I also know the organization I work in, and these were all done with regard for specific intelligence that caused us to have concerns about attempts to disrupt this event."

Several options for expanding security measures were discussed at the hearing. For example, the Homeland Security Department is developing criteria for a national identification card for U.S. citizens to carry, said retired Army Lt. Gen. Patrick Hughes, DHS' assistant secretary for information analysis.

"We are working on a national ID card issue," he said. "It's more complex than simply saying, yes, we're in favor of it or, no, we're not. It has great implications for the United States, and one of the implications is the civil liberties of individuals. We have to deal with it so we are considering the issue."

John Brennan, director of the Terrorist Threat Integration Center, said his organization is assessing information on foreigners and U.S. citizens to determine whether they are connected to transnational terrorism.

"TTIC has the national responsibility to maintain the national database on known and suspected transnational terrorists, to include U.S. citizens who are here in the United States," he said. "We have absorbed from the State Department the TIPOFF [watch list] program that has been in existence for close to 20 years. We are putting into that the names of U.S. citizens who are known or suspected to be part of transnational terrorist groups, and we work that very closely with the FBI and their domestic terrorism responsibilities."

Lee Hamilton, vice chairman of the 9/11 panel and a former Democratic congressman from Indiana, said the commission wants Congress and federal agencies to particularly accelerate border security efforts.

"What we say is that the goal is an effective biometric entry-exit screening system, that it needs to be compatible with other countries to the extent possible, so that we can exchange information about these people that cross international boundaries," Hamilton said. "And we need to have border officials who have access to ... all of the information about an individual traveler. And we think it's just common sense to have a modern, integrated border immigration system."