CHICAGO (CBS)– Classes in the Chicago Public Schools system will be canceled for an eighth day Sunday – making this teachers’ strike the longest in more than 30 years.

And as CBS 2’s Mike Puccinelli reported, the battle between CPS and the Chicago Teachers Union seems to be more getting more contentious and acrimonious. Negotiations lasted all day and late into the night Sunday – and the two sides seem to remain far apart.

CPS said as of 4 p.m., the Chicago Teachers Union said there was no possibility of a deal before the end of the day on Sunday. As a result, CPS said, it will not be possible to hold classes Monday.

That makes the 2019 teachers’ strike the longest since 1987, when classes were out for 19 school days. A total of 300,000 CPS students and 25,000 educators are affected.

At a news conference Sunday night, Mayor Lori Lightfoot did not hide her frustration with the union.

“We put everything we could, responsibly, on the table, in an attempt to get a deal done. But we have no deal to announce today, and for that I am terribly disappointed,” Lightfoot said.

Lightfoot called the deal the city was offering “the most generous in CPS history.”

She said it used recommendations from an independent factfinder that the CTU chose, which proposed a 16 percent raise that would have the average teacher “making six figures in just a few years.”

Lightfoot said the city had met teachers’ demands on a number of subjects, including sanctuary schooling. CPS Chief Executive Officer Janice Jackson said the city had also put staffing requirements in writing, and had agreed to $70 million to enforce staffing targets.

“This is, by any estimation, and incredible offer – and despite all of this, the CTU has not accepted it,” Lightfoot said. “We are enormously disappointed that CTU simply cannot take yes for an answer.”

Jackson said students are losing out in the strike, with some student athletes already having missed the opportunity to compete in the playoffs. Jackson also said high school juniors will soon need to take the PSAT to qualify for National Merit Scholarships.

Lightfoot did announce Sunday night that SEIU Local 73 – which represents support staff such as custodians, bus aides, security guards, and special education personnel in Chicago Public Schools – had come to a tentative agreement with the city.

But that has no effect on the teachers’ strike, and an SEIU representative said late Sunday that despite the agreement, members of Local 73 would be on the picket lines with the teachers again on Monday.

In a Twitter thread, the union reiterated its claim that the city can afford to fund its demands and Mayor Lightfoot is choosing not to.

“The mayor isn’t bailing out CPS. She’s raiding her CPS piggy bank to avoid taxing the wealthy donors who put her in office,” the CTU tweeted. The union claimed the mayor has shifted nearly $100 million from the CPS budget to plug the city’s greater budget hole –$60 million in pension cost shifts and $33 million for the Police Department.

She’s shifting nearly $100 million out of the Chicago Public Schools budget—money that should go to students and classrooms—and using it to plug the budget hole for the city. — ChicagoTeachersUnion (@CTULocal1) October 28, 2019

“That $93 million would support nearly 1,000 staff in CPS—social workers, nurses, case managers and teacher assistants to lower class sizes,” the union tweeted.

The CTU also claimed Mayor Lightfoot is using money for her own office that could go toward school needs.

The mayor is also using some of that funding to staff her own office. Her office is budgeted for 30 more positions and a 50 percent budget increase at the same time positions for actual city services are slashed. — ChicagoTeachersUnion (@CTULocal1) October 28, 2019

A fraction of 1 percent of the annual CPS budget stands between us and an agreement. A number of demands would cost the district virtually nothing. At this point, everyone is suffering but the person who could actually make a difference: the mayor. — ChicagoTeachersUnion (@CTULocal1) October 28, 2019

Meanwhile at a news conference Sunday night, CTU Vice President Stacy Davis Gates reiterated the union’s claim that the CTU’s latest counterproposal is separated by the city’s offer by only $38 million per year – about half a percent of the district’s $7.7 billion annual budget.

The city has said its three-year contract addresses key issues such as class sizes and staffing of nurses, librarians, social workers, case managers, and counselors.

But Gates said the city’s offer is insufficient when it comes to equity for all the city’s students. She said the city’s offer on class size protections for only “one third of the entire city,” and not every school in the CPS system.

As to librarians, Gates also claimed some city schools will get the short end of the stick with the city’s proposal.

“When they talk about equity, they forget that nine out of 10 schools that have black students – majority black students – do not have a school librarian,” Gates said.

Gates said the most egregious gap was when it comes to special education. She noted that the CPS special education program is under an Illinois state monitor because of its legal practices, and also said there were problems with special education when it comes to equity.

For one, Gates said, individualized education plans, or IEPs, for special education students, are inaccessible to immigrant parents because they are not translated.

Further, Gates said, the city has not moved on calls for restorative justice coordinators, who would “provide your child with how to deal with conflict, not how to be penalized for conflict.”

“When I hear there’s a deal on the table and we can’t say yes, I ask the question – do we say yes to injustice? Do we say yes to inequity? Do we say yes to things half done?” Gates said.

Gates also repeated that the union also wants a three-year deal when the city keeps offering a five-year deal.

In an earlier news release, Sharkey compared the situation that some private projects that have received subsidies from the city, and also the failed deal to woo Amazon HQ2 to the city – which would have involved a tax break of about $2.5 billion.

“Amazon was set to get billions of dollars in public subsidies from the city. Lincoln Yards and the 78 got billions of public dollars to bankroll their new neighborhoods for rich people—dollars that should have gone to our schools,” Sharkey said in the statement. “But CPS has yet to yield to provide a paltry fraction of those funds to support what our students need.”

Sharkey also blamed mayoral control of schools – which has been in place in Chicago since 1995 when Mayor Richard M. Daley was in office – for the labor issues.

“In 1995, the Illinois legislature gave total power and control of CPS to the mayor of Chicago, forcing us to jump through insane obstacles to get to an agreement, from super majorities to authorize a strike to constant obstacles just to bargain to get a nurse in school every day,” Sharkey said in the statement. “No other teacher or school worker in any other school district in the state confronts this kind of obstruction.”

At the news conference, Sharkey called on the mayor to “stop being so petty.”

As CBS 2’s Steven Graves reported, CPS has disputed the claim of a $38 million gap – saying the gap between the CTU and the city is actually $100 million.

“Where we are far apart is the how, not the what. How do we get there while maintaining a level of financial stability and responsibility for the district’s finances?” said CPS Chief Education Officer LaTanya McDade.

Meanwhile, the CTU said that Jackson had entered negotiations Sunday and was at the bargaining table at Malcolm X College on the Near West Side. This is the first time Jackson has joined in the negotiations since the strike began, the CTU said.

Sunday marked the 11th day of negotiations since the strike began.

CTU members earlier Sunday held a solidarity rally at the New Mount Pilgrim Missionary Baptist Church, at 4301 W. Washington Blvd. in the city’s West Garfield Park neighborhood. Faith leaders prayed and choirs sang.

BREAKING: No school Monday for CPS students as negotiations continue. This will be the 8th consecutive school day that kids will be out. It comes as CTU members held a solidarity rally at a city church where fight songs like “ROAR” by Katy Perry were played. @cbschicago https://t.co/APtn0on7cF pic.twitter.com/MXn3I7u65P — Steven Graves (@StevenGravesTV) October 27, 2019

Also Sunday, former U.S. Secretary of Education and CPS CEO Arne Duncan weighed in on the issues at a South Side church service. CBS 2 asked what he thought about the details of the deals.

“There’s always compromise,” Duncan said. “I went through two teacher negotiations and was lucky enough not to have a strike, but I’m convinced both sides, and talking to people on both sides – they absolutely want to get back to school as quick as possible, and I hope that’s coming very, very soon,” Duncan said.

On Saturday, McDade said there had been an unspecified “breach of trust” by the union after Friday’s negotiations were completed. McDade did not elaborate on the “breach of trust,” and following a CTU rally in Union Park later Saturday, Sharkey said he did not know what McDade was referring to, but said negotiations were in a “sensitive spot.”

The strike began on Thursday of last week.

With the strike set to continue Monday, it’s going to overlap with President Trump’s visit to Chicago. The president is in town for a fundraiser at Trump Tower and to speak at the International Chiefs of Police conference at McCormick Place.

Some Democrats who hope to defeat Trump in 2020 have pledged their support to the striking teachers – Sen. Elizabeth Warren joined their picket line last week. But as of Sunday afternoon, the Chicago Teachers Union had not announced any plans to participate in any protests against Trump.