"We're out here and we need to be, but I'm tired and I'm on edge," a left-wing demonstrator said on Sunday evening. "I'm also terrified," she added, noting rising tensions between the opposing groups.

President Trump blamed Portland Mayor Ted Wheeler for losing control, while the mayor responded that it was violence that Trump "helped create."

The city has seen nightly protests for about three months. And police have declared riots or unlawful assemblies about half the time. But some argue the meaning of riot is too vague to be useful.