DENVER >> Denver teachers are planning to strike Monday for the first time in 25 years after failed negotiations with the school district over base pay.

The teachers union and Denver Public Schools met Saturday in an attempt to reach a new contract after more than a year of negotiations, but both sides left disappointed.

The Denver Classroom Teachers Association released a statement after the meeting saying the district’s proposal lacks transparency and “pushes for failed incentives for some over meaningful base salary for all.”

“We will strike Monday for our students and for our profession, and perhaps then DPS will get the message and return to the bargaining table with a serious proposal aimed at solving the teacher turnover crisis in Denver,” said Henry Roman, president of the teachers union.

Meanwhile, schools Superintendent Susana Cordova said she was “extremely disappointed” that the union walked away from the table instead of continuing to work toward an agreement.

“We presented an updated proposal that responds to what we heard from our teachers, aligns to our values of equity and retention … and significantly increases the base pay for all of our educators,” Cordova said.

Teachers plan to picket around the city beginning Monday as the district tries to keep schools open by staffing them with administrators and substitutes. The district has canceled classes for about 5,000 preschoolers because it doesn’t have the staff to take care of them.

The two sides disagree about pay increases and bonuses for teachers in high-poverty schools and other schools that the district considers a priority. Teachers want lower bonuses to free up money for better overall salaries, while administrators say the bonuses are necessary to boost the academic performance of poor and minority students.

Bonuses paid to teachers with more than 14 years of experience do not become part of their base pay, which critics say encourages high turnover and hurts students. Both sides have agreed to get rid of that provision but disagree about how big the bonuses should be for teachers working in high-poverty schools and in schools deemed a high priority by the district.

Gov. Jared Polis decided Wednesday against intervening to stop the strike but said he may step in if it drags on. It’s expected to cost about $400,000 a day to keep schools operating with substitutes and administrators.

The teachers’ union says 93 percent of its members backed a strike in a vote last month.