Chicago (CNN) -- The week-old teachers strike in Chicago's public schools will continue into the new week, after a representative group of the Chicago Teachers Union decided not to end the walkout even though union leaders and school officials had reached a tentative contract deal.
The move left Mayor Rahm Emanuel vowing to go to court to force teachers back to work, calling Sunday's actions by the union "a delay of choice that is wrong for our children."
The mayor announced in a statement that he's asked city lawyers "to file an injunction in circuit court to immediately end this strike." He contended the strike is illegal because "it is over issues that are deemed by state law to be nonstrikable, and it endangers the health and safety of our children."
"I will not stand by while the children of Chicago are played as pawns in an internal dispute within a union," Emanuel said.
Members of the teachers' bargaining team detailed the proposed contract to a group of 800 union representatives, called the House of Delegates, in a meeting Sunday afternoon. But Chicago Teachers Union President Karen Lewis said that, after extensive debate, the delegates said they wanted more time to discuss the contract with union members.
The House of Delegates will reconvene Tuesday afternoon, at which point delegates could decide to end the strike -- or not. If they do, classes could resume at earliest on Wednesday. And even if the strike is ended, the more than 26,000-member union's rank-and-file would still have the opportunity at some point to accept, or reject, the proposed contract.
As of Sunday, though, Lewis said a "clear majority" of union delegates did not want to suspend the strike given the proposed contract.
"They are not happy with the agreement," Lewis said.
There were no classes all last week for more than 350,000 students in Chicago, home to the nation's third-largest school system, when the union went on strike after failing to reach a contract agreement with school board officials.
The negotiations have taken place behind closed doors. Publicly, the past week has been marked by sometimes biting remarks, as well as vocal picketing in and around the city's schools, some of which opened for a few hours each weekday to give some students a place to go during the strike.
Both sides indicated Friday that they'd reached a tentative agreement, though teachers union leaders stressed then that any decision to end the strike or not would be determined this weekend.
Lewis, from the teachers union, said that one problem is that "there's no trust" of school board members. Delegates found several elements of the contract problematic, with the union president calling job security chief among them.
"The big elephant in the room is the closing of 200 schools," Lewis said. "(Union members) are concerned about this city's decision on some level to close schools."
It was not immediately clear where Lewis got the 200 figure or when she believes such school closures might happen.
But Marielle Sainvilus, a spokeswoman for Chicago Public Schools, called Lewis' claim "false," asserting that union leaders said a few days ago that 100 schools would close, and "I'm sure it'll be another number tomorrow."
"All Ms. Lewis is trying to do is distract away from the fact that she and her leadership are using our kids as pawns in this process," Sainvilus told CNN by e-mail.
Another point of contention involves the teacher evaluation system, Lewis said. The tentative contract would change it for first time since 1967, taking into account "student growth (for the) first time," according to the school system. And those teachers who are rated as "unsatisfactory and developing" could potentially be laid off.
Principals would keep "full authority" to hire teachers, and the school system will now have hiring standards for those with credentials beyond a teacher certification. In addition, "highly rated teachers" who lost their jobs when their schools were closed can "follow their students to the consolidated school," according to a summary of the proposed contract from Chicago Public Schools.
This contract calls for longer school days for elementary and high school-age students, 10 more "instructional days" each school year and a single calendar for the entire school system, as opposed to the two schedules now in place, depending on the school.
The pay structure would change with a 3% pay hike for the first year of the contract, 2% for the second year and 2% for the third year. If a trigger extends the contract to four years, teachers would get a 3% pay increase. Union members would no longer be compensated for unused personal days, health insurance contribution rates will be frozen and the "enhanced pension program" is being eliminated.
As is, the median base salary for teachers in the Chicago public schools in 2011 was $67,974, according to the system's annual financial report.
With the strike now continuing, the school system plans to open 147 "Children First" sites citywide Monday for students to go to, in addition to programs run by the city's park department and neighborhood organizations, Chicago Board of Education President David Vitale said.
But Vitale said that he, like the mayor, is "extremely disappointed" that such programs are necessary. He noted that classes began, for some students, on August 13 and that he didn't understand why they couldn't continue as work continues to finalize a contract deal.
"There is no reason why our kids cannot be in school while the union reviews the agreement," Vitale said.
CNN's Chris Welch contributed to this report.