by Todd Feurer, CBS Chicago web producer

CHICAGO (CBS) — Mayor Lori Lightfoot on Friday said it appears the Chicago Teachers Union is “refusing to negotiate in good faith, and instead is determined to strike at all costs,” following the latest negotiating session with the Chicago Public Schools.

However, the union called the city’s latest contract proposal “a joke” that would provide only a pittance towards teachers ‘ demands for nurses, case managers, and social workers at every school.

In a statement Friday evening, Lightfoot said the CPS negotiating team presented a 72-page contract proposal on Friday that “bent over backwards to meet CTU’s concerns,” including dropping the district’s proposed changes to teacher prep times.

According to the mayor, the CPS proposal included offers regarding the union’s concerns about class sizes; staffing for nurses, counselors, and case workers; support for homeless students; and would maintain a moratorium on new charter schools.

“Unfortunately, CTU simply rejected our proposals without a counterproposal, and instead is continuing to stand on their $2.5 billion starting proposal from January on nearly all issues. That proposal included a demand to allow CTU to dictate citywide policy on affordable housing, as well as to shorten the school day and school year,” the mayor said. “It appears that CTU is refusing to negotiate in good faith, and instead is determined to strike at all costs.”

However, CTU President Jesse Sharkey said the city’s contract offer on Friday was “a joke.”

In particular, Sharkey criticized the city’s offer of $1 million over the life of the contract to reduce class sizes in grades 4-12, and $2 million over the life of the contract to recruit and train new nurses, social workers, and case managers. He said that would be only enough money for two teachers and four nurses, social workers, or case managers per year for all of CPS.

“We’re talking about an offer that frankly was insulting to us, and when you add that to the fact that they told us ‘This is our final offer, take it or leave it,’ that draws a line in the sand for us,” Sharkey said.

Lightfoot said she is prepared to continue negotiations through the weekend, but again called for CTU to provide a comprehensive written counteroffer. The mayor has said the union has not provided such an offer since she took office in May.

The union countered that the city needs to put commitments to reduce class sizes and to hire more nurses, social workers, and case managers into the contract.

“If you agree that we need smaller class sizes, if you agree that we need a nurse in every school, if you agree that we need a social worker in every school, then why won’t you put it in writing?” CTU Vice President Stacy Davis Gates said.

Lightfoot and CTU have been at odds since she took office, after the union endorsed her rival, Cook County Board President Toni Preckwinkle, and Gates suggested the mayor might be holding a grudge.

“Someone needs to ask her if this is her being petty that this union didn’t endorse her Someone has to finally ask her the question, ‘Will you jeopardize the school year for 400,000 students because you’re mad about an endorsement,” Gates said.

CTU has set a strike deadline for next Thursday, Oct. 17, if the union doesn’t have a tentative contract agreement with CPS by then.

The city has been offering teachers a 16% total raise over a five-year contract, but the union has called for a 15% total raise over a three-year deal.

“The salary is inadequate if you expect 40 kindergarteners to be in my classroom. The salary is inadequate if you expect me to work on the South Side or the West Side of Chicago that is enduring high levels of consistent gun violence, and you will not give me a social worker. The salary is inadequate if you will not give me the resources and the staffing to deal with the needs of the students,” Gates said.