ANN ARBOR, Mich. — Hundreds of students walked out of classes and blocked streets at University of Michigan as part of a planned weeklong protest against racism.

The demonstrations at the Ann Arbor school began Monday morning and included people blocking roads and sitting on medians studying. Some buses had to be rerouted and students sought other stops.

Traffic resumed within about an hour.

Organizers say the actions intended to draw attention to inconveniences experienced by the minority black student body. They cited racial epithets recently written on name tags affixed to dormitory doors and on a building.

Demonstrations also were held last week, and a fight broke out at one between a black student and a white man. The white man was arrested for disorderly conduct.