UPDATED (9:01 p.m.) – Police arrested four people at dueling rallies between the right-wing group Patriot Prayer and counter-protesters in downtown Portland Saturday.

The charges include harassment, reckless endangerment, unlawful use of weapons, disorderly conduct, resisting arrest and attempted assault of a public safety officer.

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Portland Police in riot gear stand between right-wing protesters and counter-protesters. Ericka Cruz Guevarra / OPB

The opposing factions remained largely separated Saturday by police officers who at one point blocked sidewalks to prevent the two groups from clashing.

But things turned sour, according to police, when protesters began throwing rocks and bottles.

Portland Police say officers deployed pepper spray, rubber balls, stinger rounds and aerial distraction devices after crowds failed to disperse.

Portland Fire and Rescue treated at least three people, and one was transported by ambulance for non-threatening injuries. At least one journalist with The Oregonian/OregonLive was injured with a water bottle and was seen bleeding from the head.

"The Portland Police Bureau is, and will always be, committed to providing a safe environment for all individuals to exercise their First Amendment rights in a peaceful manner," said Chief Danielle Outlaw in a statement.

"Unfortunately, today, some people chose to commit illegal acts of violence, which required members of the Police Bureau to take action in order to keep all participants and non-participants safe. This was a dangerous situation for all those involved, including officers, and I am disheartened that this kind of illegal behavior occurred in our beautiful city."

Hundreds of people converged in downtown by late morning Saturday. Police declared it a civil disturbance just before 2:30 p.m., ordering the crowds to disperse.

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A protester drips with milk, commonly used to wash out pepper spray. Ericka Cruz Guevarra / OPB

The Portland Police Bureau set up weapons checkpoints in the main protest area near the Salmon Street fountain and SW Naito Parkway. Police confiscated sticks, bats, shields and other items that could be used as weapons.

Portland Police have now declared this a civil disturbance. — Ericka Cruz Guevarra (@NotoriousECG) August 4, 2018

Traffic through the area was disrupted throughout the event, with SW Naito Parkway not passable to vehicle traffic between SW Morrison and SW Main streets due to it serving as a barrier between protesters and counter-protesters, according to police. Crosswalks were also closed to pedestrians.

The run-up to the protest garnered national attention that largely drew from perceptions of Portland's potential for "Another Charlottesville." The Southern Poverty Law Center suggested the Aug. 4 rally could be the most violent the city has seen.

The Police Bureau requested a fence be erected along the north, west and south sides of Tom McCall Waterfront Park between Southwest Salmon Street and Southwest Morrison Street for protests on Aug. 4, 2018. Portland Police Bureau

The hype largely drew from Portland's rise in clashes between right-wing protestors and counter-protestors in recent years, compounded by concern over Oregon's conceal carry law. While Oregon is an open-carry state, the law also allows local regulation of guns. Portland

bans loaded firearms

in the city without a concealed carry permit or other exemption, and the Portland Police Bureau staged weapon screening locations near the entrance to Tom McCall Waterfront Park. The bureau also deployed explosive detection dogs before and during the event.

Right-wing Patriot Prayer, Proud Boys and counter-protesters shout at one another from across a street in Downtown Portland. Ericka Cruz Guevarra / OPB

Further, Oregon does not automatically recognize concealed handgun licenses issued in other states, including Washington, where Patriot Prayer leader Joey Gibson and many of his supporters live. Gibson told OPB ahead of the rally that he would not be bringing a gun, despite earlier calls to his supporters to carry their guns at all times.

“I can’t legally carry in Portland,” Gibson confirmed to OPB in an interview. “In Portland, you have to have your concealed license.”