Cook County Circuit Court Judge Peter Flynn rejected a request by Chicago Public Schools to hold a hearing Monday that could have forced the striking teachers back to work, the Chicago Tribune reported.
Roderick Drew, a spokesman for the city's legal department, said Flynn raised the possibility of setting a hearing for Wednesday, if the strike is not over by then.
Attorneys for Chicago Public Schools filed a lawsuit Monday seeking a preliminary injunction against the strike. The attorneys said state law prohibits the Chicago Teachers Union from striking over non-economic issues.
"State law expressly prohibits the CTU from striking over non-economic issues, such as layoff and recall policies, teacher evaluations, class sizes and the length of the school day and year," the motion says. "The CTU's repeated statements and recent advertising campaign have made clear that these are exactly the subjects over which the CTU is striking."
The complaint also says the strike, which has kept 350,000 children out of the classroom for more than a week, is "a clear and present danger to public health and safety," the Chicago Tribune reported.
"It prohibits students from receiving critical educational and social services, including meals for students who otherwise may not receive proper nutrition, a safe environment during school hours and critical services for students who have special needs," the complaint said.
Karen Lewis, head of the Chicago Teachers Union, met Sunday with the union's House of Delegates to review a tentative contract but delegates decided they needed two more days to consider the deal.
Chicago Mayor Rahm Emanuel reacted angrily Sunday to the union's decision.
"I will not stand by while the children of Chicago are played as pawns in an internal dispute within a union," Emanuel said. "This was a strike of choice and is now a delay of choice that is wrong for our children. Every day our kids are kept out of school is one more day we fail in our mission: to ensure that every child in every community has an education that matches their potential."
The Chicago Teachers Union called the lawsuit "vindictive."
"CPS' spur-of-the-moment decision to seek injunctive relief some six days later appears to be a vindictive act instigated by the mayor," the union said in a statement. "This attempt to thwart our democratic process is consistent with Mayor (Rahm) Emanuel's bullying behavior toward public school educators."
The school system is offering free meals and activities for students at 147 schools, as well as at churches and local libraries, the Tribune said.