PORTLAND, Ore. (AP) — Oregon’s largest school district said late Sunday it had reached a tentative agreement with its teachers union and roughly 45,000 students would be back in school Monday after more than three weeks without classes.

The agreement must still be voted on by teachers who have been on the picket line since Nov. 1 over issues of pay, class sizes and planning time. It must also be approved by the school board, but the union agreed that classes could resume while those votes go forward. Portland Public Schools students missed 11 days of school before the district began its weeklong Thanksgiving break.

“We are relieved to have our students returning to school and know that being out of school for the last three weeks — missing classmates, teachers and learning — has been hard for everyone,” Superintendent Guadalupe Guerrero said in a statement.

The teachers' union said the tentative deal was a big win for teachers and students alike in areas of classroom size, teachers salaries, health and safety and mental health supports for children still struggling from the pandemic. Students will make up missed school days by cutting a week off winter break and adding days in the new year.

“This contract is a watershed moment for Portland students, families, and educators” said Portland Teachers Association President Angela Bonilla. “Educators have secured improvements on all our key issues. ... Educators walked picket lines alongside families, students, and allies - and because of that, our schools are getting the added investment they need.”

The deal would provide educators with a 13.8% cumulative cost-of-living increase over the next three years and about half of all educators would earn an extra 10.6% from yearly step increases, PPS said. The agreement would also add classroom time for elementary and middle grades starting next year and increase teacher planning time by 90 minutes each week for elementary and middle-aged classrooms.

The district would also triple the number of team members dedicated to supporting students' mental and emotional health.

Students last attended school on Halloween.

Many parents were supportive of the striking teachers, but as the school closures dragged on, some raised concerns about learning loss among students, especially after the long school closures during the COVID-19 pandemic. There was no online instruction during the strike.

Tensions escalated as talks continued during the Thanksgiving break, with teachers marching on Tuesday across a major bridge and stopping rush-hour traffic for about 15 minutes. One school board member's rental property was vandalized and another had posters taped to his car, Oregon Public Broadcasting reported.