European regulators raided Intel Corp. offices Tuesday, two weeks after rival U.S. chipmaker Advanced Micro Devices filed lawsuits in Japan and the United States claiming Intel broke antitrust rules.

The European Commission said it also was inspecting offices of companies that make or sell computers.

A statement from the European Union head office said the inspections involved officials from the E.U.'s antitrust department and national competition authorities. It said they visited several Intel premises in Europe.

E.U. regulators often conduct unannounced inspections of companies under investigation in competition cases.

"Investigations are being carried out in the framework of an ongoing competition case," the commission said.

Officials declined to say which offices had been searched, reveal whether documents had been taken or give further details.

Several Intel offices were "visited" by staff members from the European Commission, company spokesman Chuck Mulloy said. He declined to specify how many offices or what information investigators were seeking.

"Our normal practice is to cooperate with authorities from regulatory agencies, and that's just what we're doing in this case," he said.

According to claims filed against it, Intel has 90 percent of the world market for computer microprocessors, as measured by revenue.

For more than four years, the E.U. has been investigating claims that Intel used unfair business practices to persuade clients to buy its microprocessors to the exclusion of rivals' chips.

In March, the E.U. said it was continuing its probe after a Japanese investigation found Intel had violated antitrust rules. The E.U. cooperated with Japanese regulators.

Last month, AMD's Japan unit said it had filed two lawsuits against Intel's Japanese unit for $55 million. AMD Japan accused Intel of violating Japan's antitrust laws and said Intel's trading practices caused damage to AMD.

On June 27, AMD also sued Intel for billions of dollars in Delaware federal court, claiming that Intel strong-armed 38 computer companies into buying Intel chips. That lawsuit alleges that Intel has engaged in a "relentless" global campaign to maintain a monopoly over microprocessors.

Intel denied the allegations, saying AMD was making excuses for its secondary market position.

"Intel believes that its business practices are both fair and lawful," Marlo Thompson, a spokeswoman for the company in Munich, said Tuesday.

Intel's European headquarters in Munich. A spokeswoman said the company's practices are lawful.