WASHINGTON - LONG-simmering economic tensions between the US and China boiled over on Tuesday as the Obama administration filed its first unfair-trade case against Beijing, accusing it of restricting exports of materials needed to produce steel, aluminium and other products.

The administration vowed to protect the rights of American companies, and it got backing from the European Union, which filed its own case on the issue.

Some trade experts suggested China might settle the dispute rather than endure a prolonged hearing process before the Geneva-based World Trade Organisation, the arbiter of global trade rules.

Analysts expect the fight over China's export restrictions will be just one of many trade cases the administration files against China. President Obama made campaign pledges to take a tougher approach with US trading partners in the face of soaring job losses and the longest US recession since World War II.

The materials at issue include coke, bauxite, magnesium and silicon metal, the US complaint says.

The US and EU complaints say China's export restrictions give its companies an unfair edge over their foreign rivals by giving them access to cheaper materials, despite WTO rules against export curbs.

US Trade Representative Ron Kirk said the Obama administration decided to pursue a WTO case after two years of talks between the Chinese and the Bush administration had failed to reach a resolution. He said China's actions were endangering American jobs.

The US and EU filed separate complaints with the WTO, a step that triggers a 60-day consultation period. If the dispute is not resolved, they can formally request a WTO hearing panel. At that point, the cases likely would be merged.

If the US and EU prevail at a WTO hearing - a process that can take up to a year - and China still refuses to lift the export restrictions, the two would be given a go-ahead to impose economic sanctions on China. Those sanctions would be equal to the harm inflicted on their companies by Beijing's actions.

EU Trade Commissioner Catherine Ashton and Mr Kirk expressed hope the issue could be resolved during the consultation period. But if that doesn't happen, Kirk said the US will go forward with a WTO case. -- AP