Underscoring the difficulty US automakers have making fuel-efficient cars stateside, Ford Motor Co, announced it will be moving its Focus compact cars and C-Max hybrids out of its Michigan Assembly Plant near Detroit. The move is scheduled for 2018.

The announcement has placed worry about the long-term viability of what is one of Ford’s largest US manufacturing plants. It also casts a pall over a meeting, scheduled for just a few days from now, between Ford executives and heads of the United Auto Workers Union to forge a new labor agreement. It is expected that the UAW will ask for higher wages and keeping the status quo on healthcare. Ford has proposed cuts in healthcare benefits to trim expenses.

The company did not announce where production of the Focus and C-Max will move to. Mexico is a possibility since less than three months ago Ford said it was planning to spend $2.5 billion on transmission and engine plants in Mexico. The company also has assembly plants in Mexico which build midsize Fusion sedans and small Fiestas.

Kristina Adamski, spokeswoman for Ford, said that all decisions Ford makes is based on the necessity to keep the company competitive.

“We actively are pursuing future vehicle alternatives to produce at Michigan Assembly and will discuss this issue with United Auto Workers leadership as part of the upcoming negotiations,” she said.