AMD is suing Intel, claiming that the chip giant has abused its monopoly by illegally coercing customers into using its products.

The lawsuit, filed in Delaware, identifies 38 companies on three continents that it says were coerced by Intel, including large-scale computer makers, small system builders, wholesale distributors and retailers.

The 48-page complaint alleges that Intel used illegal subsidies to win sales and, in some cases, threatened companies with "severe consequences" for using or selling AMD products. A spokeswoman for Intel said the company had yet to receive formal notice from AMD or the US courts about a complaint. "We won't have any comment until we do," she said.

The litigation follows a recent anti-trust investigation into Intel by the Fair Trade Commission of Japan (JFTC). In March, the JFTC found that Intel had abused its monopoly power to exclude fair and open competition in the Japanese micro-processor market. The result was to substantially restrain competition, the JFTC said.

Intel's Japanese subsidiary agreed in April to refrain from several types of business practices, although it also said it disagreed with the JFTC's findings. The European Commission has also said it is pursuing an investigation against Intel for possible anti-trust violations and that it was co-operating with the Japanese authorities.

AMD's complaint lists several examples of how Intel has allegedly abused its dominate market position. One of them claims that Intel forced major customers, such as Dell, Sony, Gateway and Hitachi into exclusive deals in return for outright cash payments, discriminatory pricing or marketing subsidies.

AMD is due to discuss the suit further in a conference call later today.

Dan Nystedt in Taipei contributed to this report.