European Union industry ministers were meeting in Brussels today to discuss growing concerns that Berlin's rescue of trouble carmaker Opel may jeopardize jobs outside Germany, according to dpa. British Business Secretary Peter Mandelson fired the latest salvo with a letter to the European Commission questioning the viability of Magna International's plan to buy Opel from General Motors. "We do not believe the case has been demonstrated that the current Magna proposal is commercially the most viable plan," Mandelson wrote in the letter, extracts of which were published by the Financial Times on Thursday. Mandelson urged the EU executive in Brussels to ensure "a commercially based outcome rather than one determined by political intervention and subsidies." A commission spokesman confirmed receiving the letter, but pointed out that his office would not be taking a position until it received the official plan from Berlin, which is not likely before Sunday's German general election. "We do not expect to receive the plan before next week," Jonathan Todd, spokesman for Competition Commissioner Neelie Kroes, told the German Press Agency dpa. Opel employs more than 25,000 people in four factories in Germany, but also has plants in Belgium, Poland, Spain and Austria. Opel's sister company in Britain is called Vauxhall. Some 5,000 Opel workers rallied Wednesday in Antwerp to protest against the possible closure of Opel's Belgian plant. A similar protest was held in the Spanish town of Zaragoza on Saturday. The German government is underwriting the Magna deal with 4.5 billion euros (6.6 billion dollars) in loans and credit guarantees. But concerns that Berlin may only provide financial aid if jobs are preserved in Germany have sparked angry responses from other member states.