Chicago’s teachers union voted to approve a tentative contract agreement with city officials Wednesday but refused to end a strike that has canceled two weeks of classes unless the city’s mayor adds school days to cover that lost time.

Mayor Lori Lightfoot said Wednesday night that she would not meet that demand. Lightfoot accused the union’s top leadership of “moving the goal posts” by raising the issue Wednesday rather than in a face-to-face meeting with her on Tuesday.

“Not once during that three-and-a-half-hour meeting did they raise compensation for strike days,” Lightfoot said heatedly. “Not once.”

Lightfoot refused from the start of the strike to lengthen the school year to make up days. Chicago Public Schools CEO Janice Jackson said it would require cutting winter or spring break days or adding days to the end of the year.

Union president Jesse Sharkey said the teachers are not asking to be paid for a strike but do credit the walkout for forcing the district to compromise on some contract issues.

“Over the past two weeks we have obtained gains that are meaningful for students that will make schools better for years to come,” he said. “The commitment for nurses, social workers and resources to help homeless students are things that wouldn’t have been accomplished if we hadn’t walked the picket lines.”

Sharkey said teachers consider a refusal to make up school days “punitive” and argued that it would ultimately hurt students, including those who must take standardized tests and college admission tests this year.

“We feel like we’re just being punished because we had the audacity to defy the mayor,” Sharkey said. “And that’s not right.”

The agreement that the 700 members of the union’s House of Delegates approved on Wednesday were not immediately released but Sharkey said some of teacher’s wins could “transform” schools in the district.

Broad outlines include a 16% raise for teachers during the five-year contract, a new committee to investigate and enforce classroom sizes that surpass limits in the agreement and funding to add social workers and nurses to the city’s neediest schools.

“We’ve met them on every single issue,” Lightfoot said. “The fact that our children are not back in school tomorrow is on them.”

Union leadership said the tentative agreement does not include additional preparation time for elementary school teachers, which was a sticking point during talks this week.

The strike, which has lasted nearly two weeks, has kept more than 300,000 students out of school. Following the union’s decision, CPS canceled classes for the 11th day.

Earlier Wednesday, several high school football teams that are at risk of being locked out of the state playoffs if the walkout endures got a temporary reprieve Wednesday.

The Illinois State High School Association said in a news release that the school district agreed to let the teams practice during the strike. They would not be able to play in games on Saturday if the strike hasn’t been settled by then.

The announcement came just in time for 19 schools whose teams qualified for the state playoffs because IHSA rules require teams from schools where teachers are on strike to practice for three days before they play a game.

The teams can only practice if they find coaches that have the proper certification or meet various requirements. The district did not immediately respond to a request for comment on how many of the schools had found coaches.