DETROIT (AP) -- Carl-Peter Forster, the chief executive of General Motors Europe who runs its struggling Opel unit, will leave the company, GM said Friday.

GM said in a statement that Forster, 55, would advise the company on picking a new Opel CEO. The statement gave no time frame for his departure.

Forster will be replaced temporarily by Nick Reilly, who is now president of GM's international operations who once ran Opel's Vauxhall operations in the United Kingdom, said a person briefed on the executive moves.

The person asked not to be identified because that move has not been announced publicly.

GM will search externally for a permanent new CEO of Opel and GM Europe, likely from Germany.

GM CEO Fritz Henderson said in the statement that no other Opel management changes are expected at this time.

The person briefed on the moves said that Hans Demant will remain on as managing director and head of the Opel management board.

The executive moves come after the GM board decided this week to keep its European Opel and Vauxhall units. The board rejected a plan to sell a majority stake in Opel to a group led by Canadian auto parts maker Magna International Inc. and Russian lender Sberbank.

Forster, who has been GM's top European executive since June of 2004, advocated for the Magna deal before the sale was shot down by the GM board.

"Such a sudden shift isn't comprehensible," Forster told Germany's Bild daily Wednesday about GM's decision not to sell the units to Magna. "I hoped that it would have come to a much different outcome."

He told the paper that he didn't have an explanation for the decision from GM headquarters in Detroit either.

Asked what the restructuring of Opel would look like, Forster said: "I don't know. We have to work that out in the next days. I think the important men that decided this don't know themselves."

Forster's successor will have a difficult task of getting the European operations back on track.

Unions and employees had offered cost-cutting concessions to ease a Magna deal, such as forgoing pay increases, but those offers are now off the table and Opel workers went on strike in Europe, starting Thursday.

GM will face a new battle to secure concessions for its own restructuring plan -- and has raised the prospect of the bankruptcy of the European divisions if all parties don't work to negotiate a viable plan.

Frey reported from Frankfurt, Germany.