FLINT, MI—General Motors Co. will add 1,000 workers to build new heavy-duty pickup trucks at its assembly plant here. Priority will be given to GM workers who were laid off elsewhere.

GM has come under fire from President Donald Trump and Midwestern lawmakers for its plans to stop production at five North American factories and cut up to 15,000 jobs. The automaker has said it is trying to find new jobs for 1,500 U.S. hourly workers at the affected plants. Flint could be a haven for many of these employees.

Sales of heavy-duty pickups in the United States have grown to more than 600,000 vehicles a year, up more than 20 percent since 2013, according to industry data.