Advanced Micro Devices's (AMD) move against Intel in the US comes as the European Commission is working on its own antitrust case against the world's biggest chipmaker.

The Brussels antitrust regulator began investigating an AMD complaint against Intel five years ago, almost abandoning the case in 2002.

Its case focuses on whether Intel abused its dominant position by offering rebates that froze out rival chipmakers from the market.

A spokesman for the Commission said yesterday: "We are actively pursuing our investigation into possible violations of EU competition rules by Intel, particularly as regards its policies on rebates."

The Commission is understood to be looking at similar charges to the ones that earned Intel a warning from the Japanese Fair Trade Commission earlier this year.

AMD confirmed the Commission was investigating its complaint but declined to comment further, citing the ongoing probe.

Last summer, the Commission requested detailed information on Intel's practices from computer manufacturers and retailers.

If the regulator concludes that Intel has violated EU competition laws, it will issue formal charges and give the group the chance to respond to its allegations. Brussels could then fine Intel up to 10 per cent of global annual turnover.