Updated with a statement from CTU below and news of threatened lawsuit.

The Chicago Teachers Union (CTU) did not vote on a proposed deal Sunday, as they were expected to, meaning the strike will enter a second week.

The union's House of Delegates was expected to vote on the deal Sunday afternoon. The deal included a three-year raise schedule of a 3 percent increase in the first year followed by a 2 percent increase in the following years; an agreement to move away from so-called "merit pay" evaluation that the union opposed due to skepticism of its efficacy; an increase of 600 "special" teachers who would teach "art, music, physical education, world languages and other classes"; teacher evaluations limited to factoring only 30 percent of student test scores; reimbursements for school supplies up to $250; a guarantee that books will be purchased for students in time for the first day of classes; and more. The CTU has a detailed summary of the proposed deal on its website.

"They’re not happy with the agreement. They’d like it to be a lot better for us than it is," CTU president Karen Lewis told the Chicago Sun-Times. "No sides are ever completely happy but our members aren’t happy and they want to have the opportunity to talk to their members."

Both sides working on negotiations were optimistic on Friday that classes might resume on Monday, but without a vote on the deal from the union, the strike will continue this week.

Update: According to a statement released Sunday evening, "After a civil and frank discussion, the House of Delegates voted NOT to suspend the strike, but to allow two more days for delegates to take the information back to the picket lines and hold discussions with the over 26,000 members throughout Chicago. Teachers and school staff will return to the picket lines of the schools at which they teach at 7:30 a.m. Monday and, after picketing together, will meet to share and discuss the proposal."

The Associated Press reported Sunday evening that Mayor Rahm Emanuel said he will file a lawsuit to force an end to the strike.

"I will not stand by while the children of Chicago are played as pawns in an internal dispute within a union. This was a strike of choice, and is now a delay of choice, that is wrong for our children," Emanuel said in a statement, as reported by Reuters.

"I have instructed the City's Corporation Counsel to work with the general counsel of Chicago Public Schools to file an injunction in circuit court to immediately end this strike and get our children back in the classroom," Emanuel said.