PHOENIX (AP) - A day ahead of a scheduled walk off the job, Arizona teachers are holding walk-in protests outside public schools.

The expected walk off Thursday is an unprecedented action in the conservative state with few union protections.

Wednesday's walk-in protests are the latest staged by a grass-roots teachers group, Arizona Educators United. The group plans a rally at the state Capitol on Thursday when the walkout starts.

The group says in a Twitter post that between 30,000 and 50,000 are expected to participate in the Thursday job action with 90 school districts expected to shut down.

The teacher walkout beginning could keep hundreds of thousands of students out of school indefinitely.

The state's nearly 200 public school districts can try to keep schools open or close them.