CHICAGO (AP) – Chicago teachers uncomfortable with a tentative contract offer decided Sunday to remain on strike, insisting they need more time before deciding whether to end an acrimonious standoff with Mayor Rahm Emanuel that will keep 350,000 students out of class for at least two more days.

Emanuel fired back Sunday night by instructing city attorneys to seek a court order forcing Chicago Teachers Union members back into the classroom. “This was a strike of choice and is now a delay of choice that is wrong for our children,” he said in a statement.

Presented with a choice on whether to ask members to vote on a contract that union president Karen Lewis had at one point called “a fight for the very soul of public education,” the union’s 800-member House of Delegates told their leaders they needed more time to talk to the rank and file before ending the city’s first teachers strike in 25 years.