A coalition of leading American exporters, including Boeing, Caterpillar and General Electric, is trying to stop a “Buy America” clause being included in President Obama’s $825 billion stimulus package.

The American Steel First Act would ensure that only US-made steel was used in $64 billion of federally funded infrastructure projects.

The money, earmarked for roads, bridges and waterways, is aimed at kickstarting the economy, but the initiative by steelmakers, which secured support last week in the House of Representatives Appropriations Committee, is opposed by American exporters, who fear retaliation by foreign governments.

Their concern is given credence by the European Commission and by Eurofer, the association of European steelmakers, which said that it would urge the European Union to challenge the “Buy America” clause at the World Trade Organisation.

Gordon Moffat, director-general of Eurofer, said that the clause was a clear case of protectionism.

He said: “It looks like they are trying to shut out imports. If we have the means to attack that under WTO rules, we would urge the Commission to do so.”

A spokesman for the European Commission said that America was a signatory to the Government Procurement Agreement, a WTO treaty aimed at ensuring fair access to state investment programmes.

He said: “We would be entitled to retaliate and would certainly do so if they withdraw from [the treaty].”

Mounting evidence that governments are taking steps to shut out imports and protect domestic jobs is arousing concern at the Geneva-based trade organisation.

Pascal Lamy, the WTO director-general, will today publish a report on protectionism, highlighting a profusion of recent initiatives taken by governments, including tariffs, subsidies and a 39 per cent increase in antidumping cases between WTO members.

The global recession has led to a slowdown in international trade, exacerbated by the banking crisis.

Last month, the World Bank warned that trade volumes would contract in 2009 for the first time since 1982.

Efforts by governments to prop up the flagging automotive sectors have been hedged by undertakings to protect domestic jobs.

Last week François Fillon, the French Prime Minister, promised up to €6 billion (£5.6 billion) in aid to Renault and PSA, the owner of Peugeot-Citroën, provided that they gave a commitment to French suppliers and French employment.

“There is no question of the State helping a manufacturer which would purely and simply decide to close one or more plants in France,” Mr Fillon said.

In a letter to Nancy Pelosi, the Speaker of the House of Representatives, trade bodies such as the US Chamber of Commerce, the National Foreign Trade Council and the Aero-space Industries’ Association wrote last week: “If the United States further restricts access to our market [that is overseas consumers], these other countries will certainly follow our lead, shutting US exporters and their workers out of hundreds of billions of dollars of new business, while propping up their own national champions, to the detriment of the United States.”

The letter continued: “One issue we urge you to bear in mind as you prepare this legislation is the vitally important role that international markets play in sustaining US jobs and the role they will play in economic recovery. Without sales abroad and access to inputs, many US workers would be out of a job.”

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