The Chicago Teachers Union has given a 10-day strike notice, saying members are willing to walk off the job for the first time in 25 years.

Union President Karen Lewis said Wednesday that contract talks are faltering, with unresolved issues that include pay increases and job security.

The notice does not mean teachers necessarily will go on strike. The union could decide to continue negotiating.

The soonest teachers could go on strike is Sept. 10. Many students are already back to school. The rest begin Tuesday.

The Chicago Board of Education says it's ready to care for kids who rely on schools for meals and a safe place during the day.

Both sides already agreed on one big issue: hiring new teachers to allow for a longer school day.