A Chicago teachers strike has left 400,000 students out of school indefinitely on Monday. The strike went into effect in the country's third-largest school district, just days after the students' school year started.

An estimated 30,000 teachers and support staff have walked out after their union and school officials failed to reach a contract agreement. The strike, Chicago's first in 25 years, follows 10 months of failed negotiations between union reporesentatives and school district officials.

"Negotiations have been intense but productive, but we have failed to reach an agreement that would prevent a labor strike," Chicago Teachers Union President Karen Lewis told reporters late Sunday night.

Bullet points for the union and the school system included issues such as compensation, job security, merit pay and an evaluation system.

The mass amount of students at home leaves a reported 700 schools with empty classrooms and has prompted local police departments to upgrade the amount of operations in the area, according to CNN.

"The kids in Chicago belong in the classroom," Chicago Mayor Rahm Emanuel told reporters Sunday night, after the talks failed. "Our kids do not deserve this."

Police Superintendent Garry McCarthy told the news outlet the department will be "emptying out our offices" to send officers in administrative jobs out on the street.

While the teachers strike has left around schools open with limited hours, the district has advised parents "to first explore other options for their children."

"We know that a strike will put a strain on many families, and no one will be hurt more by a strike than our students," Chicago Public Schools said on its website.

Fox News is reporting that Dozens of civic and faith-based facilities are opening their doors to provide safe outlets to students during the strike.

An organization called Young Chicago Authors has reportedly set up programs for students in grades 6 through 12 this week.

"In collaboration with core performance artists and special guests, young people will see the power of their voices in action through film, performance and discussion," the group said.

According to CNN, Minutes before the union announced the impending strike, the president of Chicago's school board said officials offered the city's teachers a contract including pay increases and other measures they'd requested.

"We've been as responsive as we know how," David Vitale told reporters.

Vitale added that the package offered by school officials effectively guaranteed pay increases for four years, but does not include merit pay and offers "some give on the evaluation system."

"The average teacher will get a 16% raise over that (four-year) period," he said in reference to contract.

Union president Lewis agreed that "talks have been productive in many areas."

"We have successfully won concessions for nursing mothers and put more than 500 of our members back to work. We have restored some of the art, music, world language, technology and physical education classes to many of our students. The board also agreed that we will now have textbooks on the first day of school, rather than have our students and teachers wait for up to six weeks before receiving instructional materials."

While progress has seemingly been made, the talks have reportedly come up short in areas such as health benefits and evaluation procedures.

Lewis also told reporters that she was concerned about the possibility of a large termination of teachers under a new evaluation system.

"We are also concerned that too much of the evaluations will be based on students' standardized test scores. This is no way to measure teacher effectiveness at all," she said.

Mayor Emanuel said he was disappointed at the impasse Sunday night, saying he believed the offers laid out were fair to both teachers and taxpayers, but added that his staff is ready to keep working to "close the gap" between negotiators.