The union representing Boeing employees have begun a strike after about 3,200 workers at facilities in St. Louis and other locations voted to reject a modified four-year labor agreement.

Some 3,200 Boeing workers who build fighter jets in St. Louis and another Missouri site and one in Illinois are on strike, their union says.

The strike involves roughly 3,200 workers at three Boeing sites, including its St. Louis hub, which is expected to be central to the F-47 program.