A federal judge has dismissed a large portion of Advanced Micro Devices Inc.'s antitrust lawsuit against Intel Corp., saying that U.S. law does not cover many of AMD's claims.

The decision by Judge Joseph Farnan of the U.S. District Court in Delaware follows several quarters in which AMD, the world's No. 2 maker of chips used in personal computers, had taken business from its larger rival.

Sunnyvale, California-based AMD accused Intel in its 2005 lawsuit of building up a dominant market share for some microprocessors by engaging in anticompetitive conduct, including forcing major customers not to buy AMD products.

Intel, based in Santa Clara, California, countered that AMD was seeking damages mostly for lost sales of German-made, Asian-assembled microprocessors to foreign customers.

It called such damages a foreign antitrust injury (if it is one at all) for which the U.S. courts cannot provide relief, according to a May 2 court filing.

Farnan accepted this argument, concluding that he lacked jurisdiction over AMD's claims based on conduct and harm that took place outside the United States.

AMD has not demonstrated that the alleged foreign conduct of Intel has direct, substantial and foreseeable effects in the United States which gives rise to its claim, Farnan wrote in an 18-page opinion.

At best, he said AMD's allegations described activity that might have had ripple effects in the United States, but not enough to give rise to an antitrust claim.

We're pleased that the judge appears to have agreed with our view of the legal issues and the argument we made, Intel spokesman Chuck Mulloy said. He declined further comment pending a Wednesday conference with the judge.

AMD spokesman Mike Silverman said: Notwithstanding the judge's ruling today, Intel cannot escape antitrust scrutiny for its conduct wherever in the world it occurs. As this U.S. litigation is joined by global antitrust investigations, it is clear that Intel cannot escape the consequences of its illegal monopoly abuses.

Intel shares closed Tuesday at $19.96 on the Nasdaq,up 2.8 percent, while AMD shares closed down 2.9 percent at $25.99 on the New York Stock Exchange.