Chicago teachers went on strike this morning for the first time in 25 years over salary negotiations, NBC News is reporting. The strike comes after a weekend of unsuccessful 11th hour contract negotiations. The Chicago Teachers Union followed through on its promise to walk on on more than 400,000 students at 675 schools after failing to reach an agreement with the Chicago Public Schools board.

Chicago Teachers Union President Karen Lewis said “we have failed to reach an agreement that will prevent a labor strike.” The strike comes after more than a year of slow negotiations over salary, health benefits and job security. The school board unanimously voted last year to cancel the teachers’ four percent pay hike in the final year of their contract.

Chicago Public Schools enacted a plan to keep 144 schools open from 8:30am to 12:30 pm during the strike. Lewis added “this is a difficult decision and one we hoped we could’ve avoided.”

In response to the striking teachers, Chicago School Board President David Vitale said the teachers were presented with more than 20 offers during negotiations, in hopes of preventing a strike. But the teachers and the school board weren’t able to find a mutually beneficial agreement.

Vitale said there’s only a certain amount of money in the Chicago school district budget to offer to teachers. “There’s only so many things we can do that are available to us that we actually believe will not hurt the educational agenda that we think is best for our children,” he added.

Written by: Karen Benardello