Chicago teachers strike (AP image)

CHICAGO (AP) – Mayor Rahm Emanuel has asked a state court to force Chicago school teachers back to work, ending a week-long strike he calls illegal.

City attorneys asked the circuit court Monday to force Chicago Teachers Union members off the picket line and back into classrooms.

In a statement Sunday, Emanuel said the strike is illegal because it endangers students’ health and safety. Also it concerns issues such as evaluations, layoffs and recall rights that state law says cannot be grounds for a work stoppage.

The union and school leaders had seemed optimistic late last week that they would reach a resolution allowing children back into class by Monday. But teachers uncomfortable with a tentative contract offer said Sunday they needed more time to review a complicated proposal.