FRANKFURT -(Dow Jones)- German Economics Minister Rainer Bruederle said General Motors Co.'s decision to back out of the sale of its German unit Adam Opel GmbH is "completely unacceptable," speaking to journalists Wednesday.

In a surprise move, GM's board late Tuesday decided it wants to retain its core European operations, unraveling over six months of negotiations with potential bidders.

Bruederle added that GM will need to present a plan for the future of Opel and its U.K.-sister operations Vauxhall rapidly, and cautioned that workers' rights must be respected in any such plan.

-By Patrick McGroarty, Dow Jones Newswires; +49 69 29725 500; djnews.frankfurt@dowjones.com

(END) Dow Jones Newswires

11-04-09 0352ET