Opel CEO Karl-Thomas Neumann (photo above)has warned top managers that the General Motors unit’s 2016 profit target is under threat from economic setbacks, according to German daily paper Bild.

“We see strong headwinds for 2015,” the paper quoted Neumann as saying in a letter he sent to 300 of the group’s top managers. “Our next step, ‘Profitability 2016’, is by far not secured,” he said.

GM has made a turnaround of its European business, where Opel CEOs have come and gone in rapid succession, a top priority after racking up some $18 billion in losses over a dozen years.

But Opel has been hit by a plunge in Russian demand and a weak ruble that have prompted it to cut production and shed jobs in its third-biggest market.

According to Bild, Neumann sent the letter to Opel managers after being disappointed by their enthusiasm at a recent meeting of senior staff. “I was deeply disappointed with the overall level of engagement,” Bild quoted him as saying.

“I believe that many of our leaders see managing projects as their primary task instead of leading people,” he said, adding: “This is not what I expect from our top 300 leaders.”

Neumann has said he wants to return Opel to profit by 2016 at the latest and to raise the business’s operating return on sales to 5 percent by 2022, based on earnings before interest and tax (EBIT).

In June he said: “I have a lot of confidence about achieving our interim goal,” in response to a question about whether Opel will stop making losses by 2016.

In a recent interview with trade publication Automobil Produktion he said he was sticking with the target despite the slump in Russia as other areas of business were performing better than expected.

“We are fighting every day to reach that target. And we are seeing progress,” he said in the interview published on Dec. 4.