As more than 29,000 Chicago teachers walked on picket lines today, Mayor Rahm Emanuel said it was "wrong... for our children" and urged negotiators to "stay at the table."
The strike is the first teachers strike for the city in 25 years.
"This is a strike of choice and it's the wrong choice for our children and it's not necessary," Emanuel said at a news conference today. "Totally avoidable. ... We need to just finish the job... given all the work that's gone on... to make sure that our kids get the education they need."
The strike started today after this weekend's last-ditch negotiations between the Chicago Teachers Union and Chicago Public Schools failed to produce a new labor agreement.
The union represents more than 29,000 teachers in the third-largest school district in the U.S.
Negotiations between the two sides were reportedly stuck on two issues: teacher evaluations that focus heavily on standardized test scores and a benefits package for union members.
The teachers union argued that the evaluation system emphasized students' standardized test scores too heavily and unfairly penalized instructors. Emanuel said that he believed the tests would reflect better on the teachers' performances than the teachers thought.
Jesse Sharkey, the union's vice president, said today that teachers were trying to reach a contract with the city.
"I do think it happens to be that the issues we're facing in Chicago are the same issues that people are facing across the country," Sharkey said. "Public education has become an issue that's about people's rights and people's access to a high-quality future and so we think we're fighting for good public schools here and that's something worth fighting for."
Sharkey said that an atmosphere in which the school system took credit for successes and placed blame and failures on educators had created a "sense of resentment and frustration among our members."
With teachers out of the classrooms, 144 schools opened from 8:30 a.m. to 12:30 p.m. to provide breakfast, lunch and care for students.
In a city where shootings have been the story of the summer, keeping nearly 400,000 students safe during the strike immediately has become a top concern.
The teachers' labor agreement ended in June and months of negotiations failed to hatch a new deal.
Karen Lewis, the union's president, said Sunday that the strike was a difficult decision that the group had tried to avoid.
"Throughout these negotiations have I remained hopeful but determined," she said. "We must do things differently in this city if we are to provide our students with the education they so rightfully deserve."
Emanuel today said that the latest offer presented to the teachers union was a fair one.
"This offer is respectful of our teachers," he said. "It does right by our students and it is fair to our taxpayers. It is a 16 percent pay increase over four years."
Emanuel said that the two sides had made so much progress in the negotiations that the walk-out should have and could have been avoided.
The mayor said that his team was ready to resume negotiations immediately.