The Latest on a teachers strike in Chicago Public Schools, the nation's third-largest school district (all times local):

8:38 a.m.

Striking Chicago teachers say they're walking the picket lines to get more resources for students and smaller class sizes, not more money in their pockets.

From left, dance teacher Allison Greene, visual arts teacher Lucila Saldana-Olazaba and teacher's assistant Nancy Padilla pose outside Sawyer Elementary School in Chicago, Thursday, Oct. 17, 2019, on the first day of a teacher's strike. Chicago teachers went on strike Thursday after failing to reach a contract deal with the nation's third-largest school district. (Rick MajewskiChicago Sun-Times via AP)

From left, dance teacher Allison Greene, visual arts teacher Lucila Saldana-Olazaba and teacher's assistant Nancy Padilla pose outside Sawyer Elementary School in Chicago, Thursday, Oct. 17, 2019, on the first day of a teacher's strike. Chicago teachers went on strike Thursday after failing to reach a contract deal with the nation's third-largest school district. (Rick MajewskiChicago Sun-Times via AP)

Yakirah Robinson was picketing Thursday morning with about 20 other teachers and staff in front of Smyth Elementary, a predominantly black school on Chicago's near South Side. She teaches 4th and 5th grade and says she has 33 students in her classroom, many of whom need extra help.

Art teacher John Houlihan says "it's ridiculous" that kids dealing with "profound poverty" and homelessness are in classes of 30 to 40 students. He says it's "not an environment for learning."

The strike started Thursday after the Chicago Teachers Union and the nation's third-largest school district failed to reach a contract deal.

6:30 a.m.

Chicago teachers are on strike after failing to reach a contract deal with the nation's third-largest school district.

Picket lines are going up Thursday morning after the Chicago Teachers Union confirmed Wednesday night that its 25,000 members would not return to their classrooms. The strike follows months of negotiations between the union and Chicago Public Schools that failed to resolve disputes over pay and benefits, class size and teacher preparation time.

Union President Jesse Sharkey says they want a "short strike."

Mayor Lori Lightfoot was disappointed by the strike decision.

The strike is Chicago's first major walkout by teachers since 2012 and city officials announced early Wednesday that all classes were canceled for Thursday in hopes of giving more planning time to the parents of more than 300,000 students.