Action by 29,000 teachers demanding better pay set to affect the third-largest school district in the US.

Chicago school teachers have gone on strike for the first time in 25 years demanding better pay, health benefits and more resources to serve students in the third-largest school district in the US.

Monday’s strike comes less than one week after the start of the school year and after months of failed negotiations between the Chicago Teachers Union, Chicago Mayor Rahm Emanuel and the city’s school board.

Around 29,000 teachers and other staff are expected to take part in the strike voted for by 90 per cent of the Chicago Teachers Union (CTU) earlier this year.

CTU Vice President Jesse Sharkey told Al Jazeera by phone that teachers began the strike on Monday by forming picket lines at schools across Chicago.

“Nobody who works with children everyday takes the responsibility lightly,” Sharkey said. “This is weighing heavy on minds of the union and its members.

“But we feel schools are important enough to fight for and that’s what’s behind the strike. We’re going to work very hard to get it resolved quickly,” Sharkey said.

‘Unfair to children’

Emanuel, who served as President Barack Obama’s chief of staff, described on Sunday the strike as “unnecessary” and unfair to Chicago’s children.

David Vitale, Chicago school board president, said on Sunday night: “We believe that we have put on the table an agreement that should satisfy most of their needs if not all of their needs.

“We have moved dramatically from where we were earlier this year to meet [teachers’ needs] – we do not want a strike.”

Eve Rivera, a mother whose four children attend Chicago public schools on the city’s south side, told Al Jazeera over phone that she, like many parents, had heard about the possibility of the strike for months but thought it “wouldn’t happen”.

She said that she does not blame the teachers for the strike.

“Kids have suffered not because of teachers because of government,” Rivera said.

“Schools have been closed down, they shove students in one classroom and teachers still show up.”

Chicago has closed dozens of schools in recent years, and is expected to close many more.

Emanuel wants to expand the number of charter schools, which are publicly funded but privately run.

Crowded classrooms

Most charter schools are non-union and the teachers’ union argues that the city is draining funds from public schools for charters.

The Chicago School Board took back a scheduled four per cent pay raise for teachers last year, citing budget problems.

Emanuel says he is offering a two per cent pay increase annually over the next four years.

Teachers are also calling for a reduction in class sizes.

Chicago public schools average around 25 students per classroom, with some parents telling Al Jazeera that the number of students in their children’s’ classrooms can reach as high as 35.

Only about 60 per cent of high school students in Chicago graduate compared with a national average of 75 per cent and more than 90 per cent in some affluent Chicago suburbs.

The last teachers’ strike in Chicago happened in 1987 and lasted for 19 days.