NEW YORK (AP) — Saying “enough is enough,” thousands of workers at three Boeing manufacturing plants went on strike overnight less than a year after the company boosted wages to end a separate, 53-day strike by 33,000 aircraft workers.

Roughly 3,200 workers are striking at sites in Missouri and Illinois. Members of the labor union representing the workers rejected a modified contract offered by Boeing last week.

Union members who assemble Boeing's fighter jets in the St. Louis area rejected the U.S. planemaker's latest contract offer on Sunday and will strike at midnight on Monday, the International Association of Machinists and Aerospace Workers union (IAM) said.