It's approaching 11 p.m. in Portland, Oregon, and there are two main protests, said Lt. Tina Jones in a video statement on Twitter.
One group, numbering several thousand people, is gathered in Irving Park.
Another group is at an intersection near the Justice Center, where police have set up a fence. Protesters and police are now standing on opposite sides of the fence.
Some protesters there have been seen distributing fireworks and using mirrors to reflect floodlights back at police, Jones said, warning that the situation was rapidly evolving.
"Crowd is throwing projectiles at police. We are advising them to stop doing so and stop tampering with the fence. We do not want to engage the crowd. We want tonight to be peaceful," said the police department on Twitter.
Earlier today, the Portland mayor directed the police chief to no longer use tear gas to disperse crowds "unless there is a serious and immediate threat to life safety, and there is no other viable alternative for dispersal."