Boeing workers who build fighter jets went on strike Monday at midnight Central Daylight Time. About 3,200 workers at Boeing facilities in St. Louis; St. Charles, Missouri; and Mascoutah, Illinois, voted to reject a modified four-year labor agreement with Boeing, the International Association of Machinists and Aerospace Workers union said Sunday.

The IAM Union, which represents 3,200 workers currently on strike, said it had written letters to senators and representatives to press Boeing to return to the bargaining table, the group said in a statement on Wednesday.

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.

About 3,200 union members at Boeing facilities in Missouri and Illinois went on strike at midnight on Monday after rejecting an offer from the company, the union said.

STORY: More than 3,200 union members who assemble Boeing's fighter jets went on strike on Monday.The workers from the St. Louis area and Illinois rejected a second contract offer the previous day.Boeing Defense said it was ready for the work stoppage and it will implement a contingency plan that uses non-labor workers.

The latest strike at aerospace stock Boeing ($BA) continues unabated, with no talks yet on the schedule, and the strikers turning to a