Protesters were in the middle of I-35W, holding hands and signs, some sitting on the ground. Police have arrested several of them.
VIDEO: Girlfriend posts gruesome aftermath of Minnesota police shooting
There were reports of the people in the surrounding area chanting from the highway overpasses.
The shooting of Castile by police sparked outrage across the nation, with his girlfriend capturing the aftermath on Facebook Live.
About 15 trooper vehicles were on the highway, with police standing by as protesters are moved off the highway.
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