CHICAGO (AP) -- For the first time in a quarter-century, thousands of Chicago teachers walked off the job Monday, escalating a bitter contract dispute over evaluations and job security and forcing parents to scramble for somewhere to send idle children.
Both sides went back to the bargaining table around midday, hours after the walkout began when the two sides failed to agree on a contract before a midnight deadline. The strike affected nearly 400,000 public school students and their families in the nation's third-largest district.
While negotiators said they had made progress on salary and a longer school day, they remained divided on a host of other issues.
Chicago Mayor Rahm Emanuel pushed to end the confrontation quickly. He repeatedly said negotiators were within reach of a deal and that the strike was unnecessary. The mayor acknowledged tensions with union over longstanding issues, but urged a quick resolution.
"Don't take it out on the kids of Chicago if you have a problem with me," Emanuel said Monday at one of the churches that is serving as a gathering spot for students during the strike.
Some 26,000 teachers and support staff were expected to join the picket line, and events were planned all day long. At Paul Robeson High School on the city's South Side, two dozen teachers wearing red shirts chanted and carried signs saying "On Strike For Better Schools."
"There's been a large disinvestment in neighborhood public schools," said Jeremy Peters, who's taught civics and U.S. history for a decade. "It's an absolute debacle."
To give students a place to go, district officials said some 140 schools would be open for the first half of the day so children who rely on school-provided free meals can eat breakfast and lunch. More than 80 percent of district students qualify for free and reduced-price lunches.
City officials acknowledged that children left unsupervised - especially in neighborhoods with a history of gang violence - might be at risk, but Emanuel vowed to protect students.
"We will make sure our kids are safe. We will see our way through these issues, and our kids will be back in the classroom where they belong," said Emanuel, the former chief of staff to President Barack Obama.
The school district asked community organizations to provide additional programs for students, and a number of churches, libraries and other groups planned to offer day camps and other activities.
Police Chief Garry McCarthy said he would take officers off desk duty and deploy them to deal with any protests as well as the thousands of students who could be roaming the streets. Chicago police reported no problems or violence related to the strike.
Union leaders and district officials were not far apart in their negotiations on compensation, Chicago Teachers Union President Karen Lewis said. But other issues - including potential changes to health benefits and a new teacher evaluation system based partly on students' standardized test scores - remained unresolved, she said.
"This is a difficult decision and one we hoped we could have avoided," Lewis said. "We must do things differently in this city if we are to provide our students with the education they so rightfully deserve."
Republican presidential nominee Mitt Romney said Chicago teachers were turning their backs on thousands of students and that President Barack Obama was rooting for the striking educators.
Obama's top spokesman said the president has not taken sides but is urging both the teachers and the city to settle quickly.
Before the strike, some parents said they would not drop their children at strange schools where they didn't know the other students or supervising adults.
As only a trickle of students arrived at some schools, April Logan said she wouldn't leave her daughter, Ashanti, with an adult she didn't know. Ashanti started school just a week earlier.
"I don't understand this. My baby just got into school," Logan said Monday at the Benjamin Mays Academy, an elementary school, before turning around and taking her daughter home.
Some students blamed the district for interrupting their education.
"They're not hurting the teachers. They're hurting us," said Ta'Shara Edwards, a student at Robeson High School on the city's South Side. She said her mother made her come to class to do homework so she "wouldn't suck up her light bill."
But there was anger toward teachers as well.
"I think it's crazy. Why are they even going on strike?" asked Ebony Irvin, another student at Robeson.
Emanuel and union officials have much at stake. Unions and collective bargaining by public employees have come under a barrage of criticism in some parts of the country, and the Chicago dispute will be closely monitored to see who emerges with the upper hand.
The timing also may be inopportune for Emanuel, whose city administration is wrestling with a spike in murders and shootings in some neighborhoods and who just agreed to take a larger role in fundraising for Obama's re-election campaign.
The school board was offering a fair and responsible contract that would meet most of the union's demands after "extraordinarily difficult" talks, board President David Vitale said. Emanuel said the district offered teachers a 16 percent pay raise over four years, doubling an earlier offer.
Among the issues of concern, Lewis said, was a new evaluation that she said would be unfair to teachers because it relies too heavily on students' standardized test scores and does not take into account external factors that affect performance, including poverty, violence and homelessness.
She said the evaluations could result in 6,000 teachers losing their jobs within two years. City officials disagreed and said the union has not explained how it reached that conclusion.
Emanuel said the evaluation would not count in the first year, as teachers and administrators worked out any kinks. Schools CEO Jean-Claude Brizard said the evaluation "was not developed to be a hammer," but to help teachers improve.
The strike is the latest flashpoint in a public and often contentious battle between the mayor and the union.
When he took office last year, Emanuel inherited a school district facing a $700 million budget shortfall. Not long after, his administration rescinded 4 percent raises for teachers. He then asked the union to reopen its contract and accept 2 percent pay raises in exchange for lengthening the school day for students by 90 minutes. The union refused.
Emanuel, who promised a longer school day during his campaign, then attempted to go around the union by asking teachers at individual schools to waive the contract and add 90 minutes to the day. He halted the effort after being challenged by the union before the Illinois Educational Labor Relations Board.
The district and union agreed in July on how to implement the longer school day, striking a deal to hire back 477 teachers who had been laid off rather than pay regular teachers more to work longer hours. That raised hopes the contract dispute would be settled soon, but bargaining continued on the other issues.