Deal reached in Chicago teachers strike, with classes set to resume

The city of Chicago and its teachers union have reached a deal to end the city's 15-day teachers strike, with a compromise on makeup days for the time teachers spent on the picket line.

Teachers remained on strike Thursday, a day after the union voted to accept a tentative deal with the city but failed to reach a return-to-work agreement over the issue of makeup days.

The union was seeking makeup days for time lost during the work stoppage, but Chicago Mayor Lori Lightfoot initially rejected the request Wednesday night.

A deal was then reached on Thursday, allowing students to return to class on Friday, according to Chicago ABC station WLS.

The union was asking to have 11 makeup days added to the school calendar to make up for the days lost to the strike, and the two sides reached a compromise in which five days will be made up, WLS reported.

Teachers are not paid for lost days that are not made up.

"We believe this is an agreement that will produce real, lasting benefits in our schools. It's a contract we can believe in. It has meaningful improvements in class size, in staffing and in a number of other features which we believe will help transform public schools in Chicago," union president Jesse Sharkey said in announcing the base agreement Wednesday night.

Sharkey then pressed Lightfoot to extend the school year in order to make up the days lost to the strike, prompting the mayor to accuse the union of "moving the goal posts" in an effort to extract more concessions from the city.

"Not once during that (final) 3 1/2 hour meeting did they raise compensation for strike days -- not once. The issue never came up," Lightfoot said Wednesday night "I've been clear from day one that CPS would not make up any strike days. And at this late hour, we are not adding any new issues."

The mayor, however, ultimately met the union halfway in agreeing to provide five makeup days.

The Chicago Teachers Union represents the city's 25,000 teachers and educational support staff. The strike, in the nation's third-largest school district, kept more than 360,000 students out of school.

ABC News' Alex Perez contributed to this report.