DALLAS (AP) - A northeastern Pennsylvania school board accuses teachers of mounting an illegal strike and refusing to submit to mandatory arbitration.

Dallas School Board filed a state unfair labor practice charge against the teachers union. The board also alleges teachers have set a date for a second unlawful strike.The district hopes to save $500,000 in what it says are salaries and benefits that union members will not have earned because they failed to work the required 185 days.The union's chief negotiator, John Holland, says the district's complaints are "without merit." The union contends the district illegally changed the school calendar.Teachers in the district outside Wilkes-Barre have been working without a contract since 2015.