WASHINGTON (AP) _ An Internet civil liberties group said today it will file a formal complaint Friday with federal regulators alleging that new technology in Intel Corp.'s latest Pentium computer chip represents ``unfair and deceptive trade practices.''

The Washington-based Center for Democracy and Technology said it will ask the Federal Trade Commission to investigate a controversial technology built into its new Pentium III chips.

The move is the most serious challenge to Intel over privacy concerns in the new chips, which also go on sale Friday.

Other privacy groups previously organized a boycott of the new Pentium chip and asked the FTC to investigate. But none had filed a formal complaint with the regulatory agency.

An Intel spokesman declined to comment today about the threat of the FTC complaint.

The FTC has broad authority and could enjoin Intel's sale of the affected chips, although the agency's chairman, Robert Pitofsky, has already acknowledged: ``As things stand, I don't think we have the authority to do that.''

Intel, the world's largest computer chip-maker, designed its Pentium III to be able to transmit a unique serial number internally and to Web sites that request it, to help verify the identity of consumers.

The company said the technology will help online merchants eliminate fraud, but some privacy groups contend it gives companies unprecedented ability to trace a consumer's digital footprints as they wander the Web.