CHICAGO (CBS) — More than 500 teachers and other staff at Acero charter schools were walking the picket line on Tuesday, after launching the nation’s first teachers strike at a charter school network.

The Chicago Teachers Union said Acero Schools – a group of 15 charter schools for approximately 7,800 mostly Latino students – is flush with cash, but refusing to give its paraprofessionals a raise that keeps up with inflation.

The union also has demanded smaller class sizes, and increased special education resources at Acero Schools.

Acero officials said the Chicago Teachers Union walked away from the bargaining table, but CTU officials said that’s not true.

“We didn’t leave the bargaining table. We were pushed from the bargaining table by management. They have been stalling for months just in providing the most basic financial information about where they’re at,” Chicago Teachers Union spokeswoman Chris Geovanis said. “These people forced this strike, and it’s time for them to get back to the bargaining table, and put the students’ needs ahead of their own fat cat salaries.”

Acero leadership said the union is striking to try and remove students from charter classrooms, despite Acero schools ranking at Level 1 or higher.

“The sad fact is that interests from outside our community are using our students and our schools as a means to advance their national anti-charter school platform. They don’t want our schools to succeed, because it doesn’t serve their agenda,” Acero Schools CEO Richard Rodriguez said. “We’re very disappointed that union leaders have put their anti-charter political agenda ahead of the interests of our students. There’s absolutely no good reason to put students and parents through the upheaval of a strike,” Rodriguez said.

The president of the American Federation of Teachers planned to join striking Acero teachers and staff on the picket line on Tuesday. The AFT represents more than 1.7 million teachers across the country.