Andover educators and the town’s School Committee continued marathon negotiations through the weekend, blowing past an 8 p.m. deadline Sunday night and leaving open the possibility of another day of canceled classes Monday.

“They came back with the same exact offer, and they said we’re closing the schools at eight o’clock,” said Andover Education Association (AEA) President Matthew Bach at a 6 p.m. press conference Sunday. “They have decided to close the schools.”

The town said it would announce a decision on whether or not school would be cancelled Monday, but sides sailed past the 8 p.m. deadline without any decision.

Andover educators voted to authorize a strike Thursday following nine months of failed contract negotiations. Teachers took to the picket lines Friday, and classes were canceled for 5,500 public school students.

The union announced negotiations had stalled at 6 p.m. Sunday.

Through negotiations, Andover educators have cited priorities of teacher and instructional assistant pay, paid parental and family leave, protections for prep time and longer lunch and recess periods for the youngest learners.

The continued sticking point in negotiations, the union said, is now pay for teachers and instructional aides.

Saturday night, the School Committee offered a 14% raise for teachers over four years. In their proposal Sunday, the union said, the School Committee only upped that offer to 14.25% over four years.

Offered raises for aides were also insufficient, Bach said, calling the offer “a bridge too far.”

As of Saturday, the School Committee proposed a 23.4% increase over four years for all instructional assistants.

The School Committee released a statement Sunday evening saying the union’s asks would make the district’s budget “unsustainable and would result in layoffs.” The union asked for an 18% raise for teachers and a 34% raise for instructional assistants, they noted.

According to state data, the current average teacher salary is about $94,000. The starting salary for instructional assistants is $25,000, the AEA stated.

“We should say that they have paid their lawyer half a million dollars over the period of negotiations,” said Bach. … “This was a tremendous waste of everybody’s time today.”

“Although we would prefer to be in a position to offer more, we cannot ignore the reality of the severe budget implications of any additional increases,” the School Committee said in the release Sunday, noting they “recognize the current situation creates uncertainty and stress for our community.”

Massachusetts state law makes it illegal for educators or any public employees to go on strike, resulting in hefty fines. The Commonwealth Employment Relations Board ordered Andover educators to immediately return to school last week and appointed a mediator to work with both sides.

The parties found more consensus over paid family and parental leave.

After negotiations Saturday, the School Committee raised their offer to 12 weeks of parental leave, eight paid by the district and four from accrued sick time. The union has fought for 12 weeks, eight fully paid by the district but including four more 50% paid by the district, in addition to sick time to supplement.

The School Committee also said they accepted the AEA’s family leave proposal Saturday night, allowing for the use of up to 60 paid sick days to care for a seriously ill family member.

The AEA joins educator unions in Woburn, Haverhill, Malden and Brookline, which have all voted to strike since 2022 in the midst of contentious contract negotiations.

After a five-day strike in February, the Woburn union was ordered to pay a $85,000 fine to the state, $225,000 in damages to the city in damages, and an additional $20,000 to local charities.

Lance Reynolds contributed to this story.