PROVIDENCE, R.I. (AP) — Providence school bus drivers are threatening to strike only days before students head back to school.

The union that represents 200 bus drivers, Teamsters Local 251, has voted to authorize a strike in a fight to secure better retirement and pension plans.

Union business agent Nick Williams tells the Providence Journal the strike is not imminent, and the school district says it would not affect the first weeks of the school year starting Sept. 4.

The strike would affect 9,000 public elementary and middle school students, as well as private and parochial students.

District spokeswoman Laura Hart says they are working with the mayor's office and the public transit authority on contingency planning.

Williams says the bus drivers' union will give notice if the situation changes.