Police used multiple rounds of gas and flash grenades in downtown Portland to clear protesters of President Donald Trump out of the streets tonight.

Police warned protesters to leave the area surrounding Pioneer Courthouse Square over loudspeaker several times, eventually deploying tear gas and flash grenades at least four times between 8 and 9 pm.

Video by Mike Bivins

Police were dressed in riot gear, blocking streets and even rushing the street, forming a wall to clear the block.

Protesters ran from the tear gas canisters, abandoning the square known as Portland's Living Room. A woman sat on the sidewalk being helped by three people with water bottles and goggles.

The Police Bureau said on Twitter that it decided to clear the streets "due to rocks, bottles, flares, unknown liquid being thrown at officers." Protesters denied that account.

(Update, 9:53 pm: The gas used by police may not be tear gas—which is synthetic—but instead pepper gas, aka Oleoresin Capsicum, which uses the active compound in hot peppers. Both are commonly referred to as tear gas.)

The deployment of tear gas was the final statement in a show of force by police under Mayor Ted Wheeler. Police blocked the city's bridges, and effectively shut down the anti-Trump march by 8:15 pm with pepper spray and sound grenades, also known as "flash-bangs."

Skye Troy, the student body president of Washington State University in Vancouver says an officer grabbed her sign and then her back, shoving her.

"He said 'this is a restricted area' and I said, 'this is my First Amendment right," she says.

Video by Mike Bivins

The crowd appeared to have dispersed around 9 pm, but dozens of officers on vans continued to circle the block, sirens blaring.

"This isn't a protest anymore," says Timothy Jeffs, who started protesting around 3:30 this afternoon. "It's very devolved."

WW news intern Piper McDaniel contributed reporting to this story.