CNN  — 

Vigilantes might have started the violence that led to a shooting in New Mexico during a demonstration on Monday, authorities said, and the governor is vowing to hold the “instigators” fully accountable.

One man was hospitalized and another man charged with aggravated battery, Albuquerque police said.

The shooting happened during a protest in the city’s Old Town calling for the removal of a sculpture of a Spanish conquistador, officials said.

“I am horrified and disgusted beyond words,” Gov. Michelle Lujan Grisham said in a statement on Twitter condemning the “heavily armed individuals who flaunted themselves at the protest, calling themselves a ‘civil guard.’ “

“There is absolutely no space in New Mexico for any violent would-be ‘militia’ seeking to terrorize New Mexicans; and there is no space for violence of any kind on our streets and in our communities,” her statement said.

“The instigators this evening will be rooted out, they will be investigated, and they will be held accountable to the fullest extent of the law.”

The New Mexico Civil Guard, the armed militia at the protest, told CNN by email that the man is not part of their group.

A US senator said he wants a federal investigation.

“I am calling on the U.S. Department of Justice to investigate the shooting that just occurred in front of the Albuquerque Museum,” tweeted Martin Heinrich, a Democrat.

“This is not the first report of heavily armed civilian militias appearing at protests around New Mexico in recent weeks. These extremists cannot be allowed to silence peaceful protests or inflict violence.”

Protests against police brutality in the US remained mostly peaceful Monday night, though demonstrations in two other states ended in chaos.

Police in Portland, Oregon, declared a civil disturbance and closed part of downtown, they said, after some protesters lit a fire, looted a store and injured an officer with a large rock.

In Tennessee, troopers detained 21 protesters who refused to vacate Capitol grounds, they said.

Police complaint describes shooting

Albuquerque police detain members of the New Mexico Civil Guard, an armed civilian group, on Monday.

The man who was shot at the Albuquerque demonstration was taken to the University of New Mexico Hospital and is in critical condition but stable, authorities said.

Police arrested Steven Ray Baca, 31, in connection with the shooting, according to Albuquerque police. Baca is accused of aggravated battery.

According to a criminal complaint from Albuquerque police, cell phone footage recorded by a bystander shows a man in a blue shirt, later identified as Baca, appearing to protect the statue. The complaint says Baca eventually left the area of the statue but was pursued by some people from the crowd.

Videos seen and obtained by CNN from around this time show Baca pushing a woman onto the ground, and two protesters, Sradha Patel and Jonathan Juarez, told CNN the man had been harassing the protesters.

The videos do not show what occurred before Baca pushed the woman. Police note that Baca’s “specific type of interaction with the crowd is unknown at this time.”

Baca was eventually struck by a longboard and tackled to the ground by the man that hit him, the complaint says. Another “male is observed holding the end of the longboard with two hands and swinging it toward the area of Steven’s head and upper body,” the court document adds.

“At this time, a series of gunshots are heard,” the complaint says.

Baca fired four shots, according to the police complaint, and “declined to provide a statement to law enforcement.”

The police chief said he believes vigilante groups might have spurred the violence.

“We are receiving reports about vigilante groups possibly instigating this violence. If this is true, we will be holding them accountable to the fullest extent of the law, including federal hate group designation and prosecution,” Albuquerque Police Chief Michael Geier said in a news release.

Mayor Tim Keller said the shooting was a “tragic, outrageous and unacceptable act of violence,” in a tweet.

“Our hearts go out the victim, his family and witnesses whose lives were needlessly threatened tonight,” Keller said, adding that the sculpture that was the point of contention for protesters will be removed.

“This sculpture has now become an urgent matter of public safety,” the mayor said of the statue of Juan de Oñate. “In order to contain the public safety risk, the City will be removing the statue until the appropriate civic institutions can determine next steps.”

Philadelphia protest is for police officer

A demonstration in Philadelphia on Tuesday evening was in support of a police captain who was removed from command after “a volatile and chaotic situation” at the Christopher Columbus statue in South Philadelphia over the weekend, according to a statement from the Philadelphia Fraternal Order of Police.

Capt. Lou Campione’s change of command was one of several moves made Monday, according to Staff Inspector Sekou Kinebrew.

Several hundred people rallied at the statue Tuesday, calling for the city to give the captain his post back, according to CNN affiliate KYW.

Downtown Portland closed after officer injured

In Portland, police declared a civil disturbance following tense interactions with demonstrators.

One officer was injured after being hit in the head with a large rock, according to a tweet from the Portland Police Bureau.

“Due to criminal activity, this has now been declared a civil disturbance. Downtown is now closed from SW Naito to Broadway and SW Lincoln to Harvey Milk,” police tweeted. “Please leave to the North – toward Burnside. We are advising crowd to leave now or be subject to arrest or use of force.”

Fires also were lit, and one store was looted, police tweeted.

Protesters pointed lasers at officers protecting the Justice Center, according to the Multnomah County Sheriff’s Office. They also threw projectiles at law enforcement.

“We are advising the crowd to stop shaking the fence and throwing projectiles. We are here to protect the people who work in the Justice Center and the adults in custody who are living inside … Slingshots are launching objects and additional projectiles are being thrown at deputies. Stop throwing items, stop pointing lasers,” the sheriff’s office said.

As a result of the unrest, police closed downtown and made arrests, a tweet from Portland Police said.

21 detained in Tennessee

Tennessee state troopers detained 21 protesters who refused to vacate the Capitol grounds late Monday night, Tennessee Highway Patrol said in a tweet.

The demonstrators were told to leave by 11 p.m. or they would be arrested, but they refused to leave.

After several warnings, the protesters sat down and locked legs and arms, according to the highway patrol.

Of the 21 protesters arrested, 19 received citations and two were arrested for public intoxication, the agency said.

Correction: This story has been updated with the correct spelling of Steven Baca's name.

CNN’s Paul P. Murphy, Konstantin Toropin, Rebekah Riess, Artemis Moshtaghian, Jennifer Henderson and Mitch McCluskey contributed to this report.