"We believe we should resolve this tomorrow," School Board President David Vitale told the Chicago Tribune late Monday. "We are close enough to get this resolved. This is hard work."
Chicago Teachers Union President Karen Lewis responded, "Wow," when told of Vitale's comments.
"That really is up to them," she said.
Striking high school English teacher Vicki Turbov, who has two children in Chicago high schools, told the Tribune: "There is a lot of anger. This is about big stakes, the future of education in our country. This is not about a 2 percent increase."
The district has offered teachers a 3 percent raise the first year and 2 percent raises the next three years, amounting to a 16 percent raise for the average teacher over the four years when factoring in other increases, the district said.
Two other key issues involve rehiring laid-off teachers from schools that get shut down or shaken up, and a new teacher-evaluation process the union says puts too much emphasis on student test scores.
The district is the third-largest in the United States, with about 400,000 students normally attending more than 600 schools.
The district opened 144 schools as part of a strike contingency plan. Attendance was light at the schools, with some parents telling the Tribune they were uneasy about crossing picket lines.
Thousands of teachers dressed in red T-shirts swarmed peacefully through downtown and marched outside schools across the city.
The strike is Chicago's first in 25 years and the first in a major city in a half-dozen years.
Republican presidential nominee Mitt Romney said in a statement, "Teachers unions have too often made plain that their interests conflict with those of our children, and today we are seeing one of the clearest examples yet."
President Obama made no direct comment on the strike. White House spokesman Jay Carney said: "His principal concern is for the students and families who are affected by the situation. And we hope that both sides are able to come together to settle this quickly and in the best interest of Chicago's students."
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