SEATTLE — Seattle students will miss a fourth day of school on Monday as teachers go on strike for wages and classroom support.

The school district announced Sunday afternoon the cancellation of Monday classes and said negotiations with the union are underway.

“We are optimistic that an agreement will be reached soon so that students can start school,” Seattle Public Schools said.

The strike began on Wednesday, which was to be the first day of school for the district’s roughly 49,000 students.

The striking teachers said their main concern was educational and emotional support for students, especially those with special needs or learning difficulties. The Seattle Education Association said 95% of its voting members approved the strike.

In Seattle, the school district had offered wage increases an additional 1% over the 5.5% cost-of-living increase set by state lawmakers — far less than the union says it wants — plus one-time bonuses for select teachers, including $2,000 for Seattle third-grade teachers who earn an honors in English or dual language.

The union says it opposes the district’s efforts to eliminate staffing ratios for special education students, saying it will mean more work for general education teachers and teachers in special education.

Districts across the country have faced labor challenges as the pandemic has placed extraordinary pressure on teachers and students.