Boeing Co. said Tuesday it would lay off about 250 workers at its Wichita operations, partly because of program delays caused by a recent machinists strike.

The announcement came on the same day the aerospace manufacturer began contract negotiations with its engineers in Wichita.

The layoffs include cuts at the Integrated Defense Systems unit. Officials attributed the cuts to delays in major programs due to a work stoppage that ended Sept. 30, when about 18,400 Boeing machinists in the Pacific Northwest and Wichita returned to work after a four-week strike that shut down the company’s commercial airplane assembly plants and slowed work at its Wichita defense facility.