General Motors' decision to keep its European arm Opel after months of negotiations to sell it triggered anger and dismay in Europe and especially in Germany, which had led the talks and was putting up much of the cash. The European trade unions have called for strike action.

The morning and evening shifts at the Opel plant in Antwerp will strike on Friday.  The night shift will strike Sunday evening, according to Rudi Kennes of the socialist trade union ABVV.

General Motors reversed course on Tuesday by abandoning a long-expected sale of Opel to a group led by Canadian auto supplier Magna. GM opted to keep the European unit after a year of uncertainty and high-level political negotiations.

GM said improving business conditions and the strategic importance of Opel had prompted the unexpected move by its 13-member board of directors appointed in the wake of its own bankruptcy just four months ago.

Chairman of the European Opel works council called on all Opel plants to strike on Thursday. "This is a black day for Opel," said chairman Klaus Franz.

Only yesterday the trade unions had reached an accord with Magna to cut personnel costs by tens of millions over the next 10 years. Now that the takeover is not materialising they sat the deal is dea in the water.