PORTLAND, Ore. — Hundreds of people gathered for rallies and marches against police violence and racial injustice Saturday night in Portland, Oregon, as often violent nightly demonstrations that have happened for 100 days since George Floyd was killed showed no signs of ceasing.

Molotov cocktails thrown in the street during a march sparked a large fire and prompted police to declare a riot. Video posted online appeared to show tear gas being deployed to clear protesters from what police said was an unpermitted demonstration. Arrests were made, but it wasn’t immediately clear how many.

At least one community member was injured, police said. People were “engaging in tumultuous and violent conduct thereby intentionally or recklessly creating a grave risk of causing public alarm,” the department tweeted. “Fire bombs were thrown at officers.”