federal grants to local governments for equipment and training to help combat terrorism. Most of the money paid for emergency drills and upgrades to basic items, from radios to fences. But the department also has doled out millions on surveillance cameras, transforming city streets and parks into places under constant observation.

The department will not say how much of its taxpayer-funded grants have gone to cameras. But a Globe search of local newspapers and congressional press releases shows that a large number of new surveillance systems, costing at least tens and probably hundreds of millions of dollars, are being simultaneously installed around the country as part of homeland security grants.

In the last month, cities that have moved forward on plans for surveillance networks financed by the Homeland Security Department include St. Paul, which got a $1.2 million grant for 60 cameras for downtown; Madison, Wis., which is buying a 32-camera network with a $388,000 grant; and Pittsburgh, which is adding 83 cameras to its downtown with a $2.58 million grant.

Small towns are also getting their share of the federal money for surveillance to thwart crime and terrorism.

Recent examples include Liberty, Kan. (population 95), which accepted a federal grant to install a $5,000 G2 Sentinel camera in its park, and Scottsbluff, Neb. (population 14,000), where police used a $180,000 Homeland Security Department grant to purchase four closed-circuit digital cameras and two monitors, a system originally designed for Times Square in New York City.

"We certainly wouldn't have been able to purchase this system without those funds," police Captain Brian Wasson told the Scottsbluff Star-Herald.

Other large cities and small towns have also joined in since 2003. Federal money is helping New York, Baltimore, and Chicago build massive surveillance systems that may also link thousands of privately owned security cameras. Boston has installed about 500 cameras in the MBTA system, funded in part with homeland security funds.

Marc Rotenberg, director of the Electronic Privacy Information Center, said Homeland Security Department is the primary driver in spreading surveillance cameras, making their adoption more attractive by offering federal money to city and state leaders.

Homeland Security Department spokesman Russ Knocke said that it is difficult to say how much money has been spent on surveillance cameras because many grants awarded to states or cities contained money for cameras and other equipment. Knocke defended the funding of video networks as a valuable tool for protecting the nation. "We will encourage their use in the future," he added.

But privacy rights advocates say that the technology is putting at risk something that is hard to define but is core to personal autonomy. The proliferation of cameras could mean that Americans will feel less free because legal public behavior -- attending a political rally, entering a doctor's office, or even joking with friends in a park -- will leave a permanent record, retrievable by authorities at any time.

Businesses and government buildings have used closed-circuit cameras for decades, so it is nothing new to be videotaped at an ATM machine. But technology specialists say the growing surveillance networks are potentially more powerful than anything the public has experienced.

Until recently, most surveillance cameras produced only grainy analog feeds and had to be stored on bulky videotape cassettes. But the new, cutting-edge cameras produce clearer, more detailed images. Moreover, because these videos are digital, they can be easily transmitted, copied, and stored indefinitely on ever-cheaper hard-drive space.

In addition, police officers cannot be everywhere at once, and in the past someone had to watch a monitor, limiting how large or powerful a surveillance network could be.

But technicians are developing ways to use computers to process real-time and stored digital video, including license-plate readers, face-recognition scanners, and software that detects "anomalous behavior." Although still primitive, these technologies are improving, some with help from research grants by the Homeland Security Department's Science and Technology Directorate.

"Being able to collect this much data on people is going to be very powerful, and it opens people up for abuses of power," said Jennifer King, a professor at the University of California at Berkeley who studies privacy and technology. "The problem with explaining this scenario is that today it's a little futuristic. [A major loss of privacy] is a low risk today, but five years from now it will present a higher risk."

As this technological capacity evolves, it will be far easier for individuals to attract police suspicion simply for acting differently and far easier for police to track that person's movement closely, including retracing their steps backwards in time. It will also create a greater risk that the officials who control the cameras could use them for personal or political gain, specialists said.

The expanded use of surveillance in the name of fighting terrorism has proved controversial in other arenas, as with the recent debate over President Bush's programs for eavesdropping on Americans' international phone calls and e-mails without a warrant.

But public support for installing more surveillance cameras in public places, both as a means of fighting terrorism and other crime, appears to be strong. Last month, an ABC News/Washington Post poll found that 71 percent of Americans favored increased use of surveillance cameras, while 25 percent opposed it.

Still, some homeland security specialists point to studies showing that cameras are not effective in deterring crime or terrorism. Although video can be useful in apprehending suspects after a crime or attack, the specialists say that the money used to buy and maintain cameras would be better spent on hiring more police.

That view is not universal. David Heyman, the homeland security policy director at the Center for Strategic and International Studies, pointed out that cameras can help catch terrorists before they have time to launch a second attack. Several recent failed terrorist attacks in England were followed by quick arrests due in part to surveillance video.

Earlier this month, Senator Joe Lieberman, independent of Connecticut, proposed an amendment that would require the Homeland Security Department to develop a "national strategy" for the use of surveillance cameras, from more effectively using them to thwart terrorism to establishing rules to protect civil liberties.

"A national strategy for [surveillance cameras] use would help officials at the federal, state, and local levels use [surveillance] systems effectively to protect citizens, while at the same time making sure that appropriate civil liberties protections are implemented for the use of cameras and recorded data," Lieberman said.