RUESSELSHEIM, Germany (AP) - General Motors top executives are reaffirming their commitment to Opel, their lossmaking European subsidiary, during a visit to the company's German headquarters. GM Chairman and CEO Dan Akerson said at a news conference Wednesday that GM was "fully supportive of the Opel turnaround plan" and that the Detroit-based group "must have a strong presence in Europe and especially here in Germany." Akerson added that GM was committed to investing 4 billion euros ($5.22 billion) in Europe by 2016 but did not announce any new plant closings or measures to improve earnings. Hundreds of Opel employees packed the Opel headquarters to hear Akerson and GM board chair Steve Girsky speak. The company is set to close its plant in Bochum by the end of 2014 after employees rejected a restructuring agreement.