For the second time in a month, Berkeley was the scene of violent demonstrations as supporters of President Trump clashed with counter-protesters Saturday on the streets of the city.
At least 10 people were arrested and seven others were injured as a series of disturbances marred what was supposed to be a pro-Trump rally in the famously liberal community.
The unrest underscores the heightened political tensions that have taken hold since Trump took office in January.
Last month a scheduled appearance by conservative provocateur Milo Yiannopoulos was canceled amid a violent protest on the UC Berkeley campus. That sparked a national debate — in which Trump himself took part — about the line between the right to demonstrate and protecting free speech that some find objectionable.
Saturday's "March 4 Trump" rally, one of several held across the country, began at Martin Luther King Jr. Civic Center Park about 2 p.m.
The Trump supporters marched several blocks but were met by a group of counter-demonstrators, and fights began breaking out, according to Matthai Chakko, a spokesman for the city of Berkeley.
Videos and photos posted on Twitter showed people punching each other and pulling their hair, with one man using an unidentified object to beat another person. Several people in the crowd were pepper-sprayed, including an elderly man.
At least two people, with their faces covered up, could be seen on video trying to set fire to an American flag, while a photo on Twitter showed the bloody face of a man who wore a T-shirt that said "Trump is My President."
Amy Leona Masker, a 23-year-old student from Las Positas College in Livermore who was on crutches, was among the counter-demonstrators. She and a fellow student were standing together when they saw the fighting break out.
"These crutches came in handy when people started shoving," Masker said.
She and the other student said one of the Trump supporters, who wore a gas mask and had a wooden shield, was one of the pepper-sprayers. They said there were several isolated fights, but when they erupted, people from both sides tried to break them up.
Masker said she came out to "support what really is our country."
Nancy Chase, who held a sign reading "Grandmothers for Trump," told an SFGATE reporter that she was there to show support for the president "in a positive way."
"I'm not looking for violence," she said. "These people just want to fight. They are anarchists in black, and it's not what we are about. I just want to stand up for liberty."
David Tomes, another pro-Trump marcher, told the Bay Area newspaper, said "this is the most immature and disgusting display of human interaction."
Berkeley Police Officer Byron White said 10 arrests were made: one for resisting arrest, four for assault with a deadly weapon, including a dagger, and five for battery. About seven medical evaluations were made on the scene. None of the injured wanted to be taken to the hospital.
Chakko said among the other items police confiscated at the rally were metal pipes, bats and two-by-fours.
"A group of people carrying bricks were detained and the bricks were confiscated," he said.
City and Berkeley Police Department officials said they were aware of the rally and had prepared for it. They said other groups besides Trump supporters and protesters were also at the rally.
The pro-Trump rally was part of a nationwide effort to show support for the president and his "America First" policies, according to the website of Main Street Patriots, one of the organizers.
"With high-profile acts of terrorism at home and abroad, with police shootings in the headlines and police officers dead in the line of duty, the government's first duty to keep the country safe has to be addressed," the group's website states.
City officials express disappointment at the violence.
Berkeley was not the only city that reported clashes between demonstrators.
Six people protesting a Trump rally in St. Paul, Minn., were arrested on felony riot charges after they lit fireworks inside the Minnesota State Capitol and fled, police told the Associated Press. About 400 people attended the St. Paul event, and about 50 showed up to protest it. Some other minor scuffles between the dueling demonstrators were quickly defused.
In Nashville, two people were arrested as protesters clashed with Trump supporters at the Tennessee Capitol. The groups at times cursed at each other and made physical contact, which state troopers broke up, NPR affiliate WPLN reported.
Near Mar-a-Lago, where Trump is spending the weekend at his private estate, the Palm Beach Post reported that people on both sides exchanged profanity. Trump's motorcade briefly stopped so he could wave at supporters.
At least some of the counter-protesters appeared to be members of the so-called black bloc, a group that UC Berkeley officials blamed for many of the problems on campus last month.
The self-described anarchists or anti-fascists have left school and law enforcement officials struggling to cope with their tactics.
The term "black bloc" was used to describe the tight wedges of black-clad protesters in helmets and masks who appeared in street demonstrations in Germany in the 1970s, confounding efforts to single out, identify and prosecute individuals.
King reported from Berkeley and Vives from Los Angeles.
March 5, 8 a.m.: This story has been updated with a quote from Berkeley councilman.
6:45 p.m: This article was updated with a new top and tweaks throughout.
5:55 p.m.: This article was updated with the number of arrests and injuries and comments from a city official.
4:55 p.m.: This article was updated with new information from authorities about the rally.
4:20 p.m.: This article was updated with new details on the march.