Corrections & Clarifications: In a previous version of this story, an incorrect title was given for Tucson Vice Mayor Regina Romero.

What had been a peaceful rally near the Phoenix Convention Center to protest President Donald Trump's speech Tuesday night turned combustible afterward, with police deploying pepper spray and stun grenades to disperse the large crowd.

Police said some anti-Trump protesters threw rocks and bottles, and officers responded with pepper balls, pepper spray and gas.

It was a chaotic ending to hours of protests that had generated tension but little violence.

One eyewitness said he saw water bottles thrown at police while other protesters said they saw no provocation.

Kylee Whiteagle, 19, Phoenix, said demonstrators were peacefully protesting in front of the convention center.

"Police started throwing tear gas and pepper-spray pellets and flash bombs to basically make us run away," she said.

The police actions started about 8:48 p.m.,shortly after Trump finished speaking.

Carson Harris, 22, of Tempe, who joined the protest against Trump at about 5:45 p.m. Tuesday, was standing just east of the Herberger Theater Center near Third and Monroe streets when he saw several protesters behind barricades “throwing empty water bottles and yelling at police.”

Then he saw a “small spinning firework or something” thrown toward police. It landed in the street.

“That’s when they started spraying tear gas,” Harris said, referring to police.

At a news conference late Tuesday, Phoenix Police Chief Jeri Williams said she was told that protesters had thrown tear gas at officers near the Herberger Theater Center.

She said she believed officers responded appropriately, given the charged and emotional nature of the event.

No serious injuries were reported other than those that were heat-related, Williams said.

The Phoenix Fire Department treated 26 people for that, with two taken to hospitals for evaluation. No property damage was reported.

"Kudos to our community," Williams said.

Williams and Mayor Greg Stanton said an after-incident review would be conducted.

Stanton said he would have further comments after that review.

They emphasized that the city's top priority had been accomplished: getting those who had come to the rally home safely, and getting police home safely.

Four arrests were made as of 10:30 p.m., Williams said.

Two arrests were made on suspicion of assaulting a police officer, one on suspicion of criminal damage and another was made on an unrelated misdemeanor warrant, police said.

After a two-story cloud of gas rose over the streets for several blocks, protesters fled in every direction to escape the gas. Nonetheless, Harris said, none of the protesters he saw crossed the barrier lines established by police, instead running away from the convention center.

At least a dozen protest groups had melded together outside the center in downtown Phoenix throughout the afternoon and evening under a common cause to oppose the president's policies.

Anti-Trump protesters yelled "shame" and thrust their handmade signs into the air as a long line of people entered the convention hall to hear the president speak.

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A group of pro-Trump bikers said they traveled to the area to help ensure the president's supporters were able to attend the rally.

The gathering before the Trump rally was peaceful.

As of early Tuesday evening, the gathering outside the Trump rally was large but still relatively peaceful.

Before Trump's speech began, police stood in riot gear on Monroe and Second streets between protesters and Trump supporters. The two crowds had two barriers, and the street, between them. A police helicopter circled above the crowd.

As the president's speech went on, and the protest crowd stayed relatively large, more police officers in riot gear entered the area

More than 100 people poured into Civic Space Park along Central Avenue after the speech where stacks of free water bottles and medics stayed under a ramada.

Pete Facundo treated attendees who had been sprayed or gassed. Young men stripped their shirts off, saying they felt the burn and sting on their chests.

"I totally expected this to happen ... just craziness in the street," he said. "As soon as I heard that first shot, I saw people running."

Jacob Chinarian, 20, of Tempe said he was standing in front of the convention center with a large group when “I saw one person throw a water bottle and they (police) responded with tear gas and rubber bullets. I saw several people get hit. They opened fire into areas where no one threw anything."

Chinarian said gas got into his eyes and he ran.

Mesa resident Carolina Hernandez, 23, was heading north on Central Avenue when she heard flash bangs go off on hundreds of protesters who lingered more than an hour after Trump finished his speech.

Hernandez said she saw an 11-year-old girl get gassed.

"It's crazy, and it's sad," she said.

Hernandez stayed with the remaining protesters. She wore a medical mask and carried a cold bottle of Milk of Magnesia to help others who had been gassed.

The rally outside the convention center drew organized groups as well as individuals.

Hundreds of people met at Civic Space Park near Arizona State University's downtown campus before walking to a protest at the Herberger Theater Center near the Trump rally venue.

Some wore Bernie Sanders and Black Lives Matter T-shirts. Another group identified itself as the "John Brown Group" and carried AR-15-style guns.

Many organizations such as Puente, the One Arizona coalition, Mi Familia Vota, and Progressive Democrats of America were present.

They chanted anti-Trump and anti-fascism slogans as they gathered in front of the theater.

Others used song to make their point.

Congregation members from the Unitarian Universalist Church broke up shouting and chanting, leading the crowd in the gospel song “This Little Light of Mine.”

"I don't know why they keep shouting 'USA.' We just keep shouting it back. We believe in the same country, just not the direction they are going in," said Anne Schneider, the former dean of the College of Public Programs at Arizona State University.

Individuals gathered, too

Melanie French wasn't part of an organized protest group but decided to show up with her family and hold a handmade sign with an image of the state of Arizona that said, "Mr. Hate Leave My State."

The 44-year-old registered nurse from Ahwatukee Foothills stood in the 106-degree heat near the edge of where protesters gathered north of the convention center and vowed to stay "until I run out of water or run out of steam."

As she stood holding her sign, a steady stream of protesters made their way onto Second Street, which had been blocked off by police south of Van Buren Street.

Earlier in the afternoon, a number of individual protesters gathered across the street from the convention center on Second Street just south of Monroe. Phoenix police closed Second Street to traffic, and the long line of people waiting to enter the convention center snaked all the way down Second Street and then east along Washington Street.

Cathy Harvard of Phoenix held a handmade sign that said, "Impeach." The 58-year-old receptionist said this was the first Trump event that she protested, and felt strongly she needed to be outside the convention center to speak her mind. She left work at 1 p.m. to get to a spot outside the convention center.

"I do not like that man. He does not belong in the White House," she said. "He needs to be impeached. He needs to go."

Standing in the shade across from the convention center, she wiped her brow with a washcloth. She wasn't finished with her complaints.

"He shouldn't even be in Arizona. He's out having a campaign rally. Like someone is going to vote for him in 2020?"

Pro-Trump bikers, supporters arrive

A group calling itself Bikers for Trump gathered near the Burton Barr Central Library earlier on Tuesday. Their goal was to ensure that the marches outside the rally remained peaceful, said Jim Williams, known as "Reverend Jim" to his fellow riders.

“These people have a right to go in and hear what the president has to say,” Williams said.

Bikers for Trump is a loose-knit group — some riders who showed up said they had never rode with them before. Williams said he has ridden with Bikers USA — United for Sovereign America — for about a decade.

After riding from the downtown library, about 50 members of the group marched to the corner of Second and Monroe streets, where they were met with words of thanks by rally attendees.

Hundreds were in line to watch Trump speak.

Holding a yellow "tea party" "Don't Tread On Me" flag, Retta Buntin of Gold Canyon said she came out to "support the president."

"He's more concerned with people than with politics," Buntin said.

David Harris, her high-school friend, who was holding the other end of the tea-party flag, joined in.

"I don't remember anytime in our lives when the president was so available to his base," Harris said.

By 5:30 p.m., hundreds, some who brought young children, were still waiting in line to enter into the convention center.

Pro-Jewish supporters gather at Capitol

Farther west at the Arizona Capitol, hundreds of people from Arizona’s Jewish community and their allies gathered on the lawn late Tuesday afternoon to denounce what they described as a startling resurgence in neo-Nazism and racism around the country.

Rabbis and Jewish political leaders from the Valley led the rally. Recounting the horrors of the Holocaust that killed more than 6 million Jews, they demanded Trump unequivocally reject white-supremacist groups.

Sarah Kader, of the Arizona Jewish Lawyers Association, told the story of her grandmother, who survived being tortured, beaten and starved in the Auschwitz concentration camp.

“I saw the number tattooed on her arm by the Nazis,” Kader said.

After the rally, hundreds of people marched toward downtown Phoenix to join the other protests.

Possible Arpaio pardon draws criticism

Earlier Tuesday afternoon, the non-profit Mi Familia Vota hosted a news conference outside St. Mary's Basilica to denounce Trump's visit to Phoenix and his potential to pardon former Maricopa County Sheriff Joe Arpaio.

Various organizations who condemn Trump's possible pardon came together to speak out against him.

"We are here to march together in unity to call to what has been, for a very long time, in our faces: plain and uncovered racism. We are here to call it out," Tucson Vice Mayor Regina Romero said.

A White House spokeswoman said later in the day that Trump would not issue a pardon Tuesday. But during his speech, the president hinted that he would pardon Arpaio at a future date.

Outside the convention center, people shared the news with each other.

Moments after word began to spread of a possible pardon, John Schnautz of Phoenix said it would only inflame the situation, if not Tuesday, then when it officially happens.

"It's like 'The Apprentice.' It's the cliffhanger!" he said, referring to the TV show made popular by Trump. "That's what we're doing here. He had the nerve to do this tonight in Phoenix, Arizona, with all we've got going on."

Montini:Why didn’t 40,000 Boy Scouts walk out on Trump? | My Turn:Trump embodies every one of the Seven Deadly Sins | Our View:Here's how to protest Trump

Republic reporters Craig Harris, Alden Woods, Ricardo Cano, Jessica Boehm, Daniel González, Laura Gómez, Jason Pohl, Megan Janetsky, Ron Dungan, Dianna M. Náñez, Dawn Gilbertson, Garrett Mitchell, Pat Flannery, Dawn Gilbertson, and Gabriella Del Rio contributed to this article.

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