DALLAS, Pa. — A northeastern Pennsylvania school board has voted to withhold a week’s pay from teachers that went on strike, saying the district will be short of offering a state-mandated 180 days of classes as a result.

But the teacher’s union in the Dallas School District plans to file a grievance, saying the district could have made up the days over Christmas break or using other calendar adjustments.

Dallas teachers haven’t had a contract since September 2015 and say they’ll strike again Sept. 5 if that doesn’t change.

The school board has a pending unfair labor practice complaint against the union, claiming it mounted an illegal strike and refused to submit to mandatory arbitration.

The teachers picketed from Nov. 14 to Dec. 19, which the district claims was six days too long.