"We are in discussions with our German unions and others throughout Europe," CEO Dan Akerson told reporters before GM's annual shareholders meeting. "They're constructive, they're professional, and it's our hope and expectation that we'll come to some sort of mutual understanding."

Akerson declined to address whether the future of a plant in Bochum, Germany will be discussed by the GM board at its meeting later Tuesday.

When asked whether the talks with unions would cover Bochum's future, Akerson said they relate to all GM's European plants.

GM is hosting its second annual meeting since emerging from bankruptcy in 2009 and going public in late 2010. The largest U.S. automaker is facing an increasingly difficult environment in Europe, where demand has drastically declined during the region's financial crisis.

Akerson said Europe — where it has lost money the last 12 years — is the company's most important issue. "We have to fix Europe or at least get it to where it isn't draining the corporate coffers," he said.

GM's Europe business posted a first-quarter loss of $256 million.

In late February, GM announced an alliance with French automaker Peugeot Citroen SA in hopes of reversing years of losses at its Opel unit. But many analysts have questioned the benefits of this alliance.

Akerson said in March it may be two years before the European division is profitable again as the continent sheds overcapacity. He believes the overall industry has between seven to 10 excess car plants in the region.

Analysts expect GM to disclose more details about its plan to turn around the Europe business at Opel's June 28 board meeting.

Investors have been focused on the turnaround at Opel, which GM opted to keep in 2009 after halting a planned sale.

In November, Akerson signaled his growing impatience by naming Vice Chairman Steve Girsky to head the supervisory board at Opel. The unit posted a $747 million loss last year.

Speculation that Bochum would close intensified after GM said last month it would halt Astra production at Opel's main plant in Ruesselsheim, Germany, with the car only to be made in Britain's Ellesmere Port and Gliwice in Poland.

GM executives have refused to promise workers in Bochum their jobs would be safe after the company's current labor deal with German union IG Metall expires at the end of 2014.

Bochum directly employs around 3,100 people, and unions have said many more workers at suppliers and other businesses depend on the plant.