Hundreds of powerful computers at the Defense Department and U.S. Senate were hijacked by hackers who used them to send spam e-mail, federal authorities say.

The use of government computers was uncovered during the Justice Department's recent cybercrime crackdown. It adds another wrinkle to the use of so-called zombie PCs, which number in the millions and have bedeviled consumers and universities the past year.

Hackers gain secret control of the computers by sending e-mail viruses and worms or by planting software code on Web sites.

The takeover of government computers is part of a bounty of evidence of new online scams that could lead to more busts under the crackdown, says Dan Larkin, unit chief of the Internet Crime Complaint Center. Authorities are in the process of repairing the government computers.

Operation Web Snare, aided by analysts at the National Cyber-Forensics & Training Alliance, a non-profit group here supported by the FBI, tech companies and academia, netted more than 150 arrests and equipment involving dozens of spammers and online fraudsters. It uncovered new:

* Phishing schemes. A recent wave of such attacks, in which e-mail directs consumers to bogus Web pages to trick them into surrendering personal information, makes use of new digital tricks.

One technique superimposes the image of what looks like a legitimate site, including its Web address, on the users' computer screen. The site is a fake. Another overlays a bogus pop-up window in front of an authentic site. Both methods have targeted SunTrust bank customers, the NCFTA says.

* Spam. A recent influx of spam goes undetected by some spam filters. It uses digital images containing text so it looks like art. Another form, with bogus appointments in the subject header, has fooled people into opening it.

"Spam is just the vehicle," says Liz Christopher, a Microsoft official who doubles as a digital-integrity investigator for the NCFTA. "From it, comes phishing, ID theft, zombie PCs, you name it."

* Electronic attacks. Employing a new motive to an old crime, Orbit Communication, which resold satellite television systems, hired hackers to launch electronic attacks against business rivals' Web sites, a federal indictment says.

The attack differs from most, which are often used to extort money from offshore gambling Web sites and banks.

The broad sweep �� the federal government's fourth in three years �� suggests federal, state and local authorities are making inroads into cybercrime after years of false starts. Operation Web Snare is not the end but rather the start of such investigations, Larkin says.

Source: Agencies