Daimler Trucks North America said Tuesday it was warning thousands of workers that potentially large layoffs could be coming at manufacturing plants in North Carolina, South Carolina, Oregon and Mexico.

The company said in a statement that it was notifying production workers about the layoffs two months in advance, in compliance with federal law. More details were expected to be released Thursday.

Portland-based Daimler Trucks employs about 20,000 workers building Freightliner and Western Star trucks and Thomas Built school buses, along with engines and parts. The unit is a division of Stuttgart, Germany-based Daimler AG.