FERGUSON, Mo. (AP) — Authorities have started arresting protesters who were planning to block part of Interstate 70 near the St. Louis suburb where an unarmed black 18-year-old was fatally shot by a white police officer.

Groups of protesters were gathering in the middle of a road near interstate on-ramps Wednesday ahead of their plans to block access to the highway. After being warned to stay out of the street, some refused, and an Associated press reporter saw at least 7 cuffed by police.

Organizers say they want to bring rush hour traffic on I-70 in Ferguson to a standstill and expect to be arrested.

The Missouri State Highway Patrol and city and county police departments say they will "enforce the law and ensure public safety" at the protest.