SAN JOSE (BCN) — San Jose city officials Friday condemned violence that took place at Donald Trump’s campaign rally Thursday night that left some people bloodied, led to four arrests and injured a police officer.

Police said that about 300 to 400 protestors gathered outside the presumed Republican presidential nominee’s rally that was expected to draw 12,000 to 15,000 supporters and started at 7 p.m. in the South Hall of the San Jose Convention Center.

A police officer suffered a minor injury to his wrist when someone threw a metal object at the officer and three people were arrested for assault with a deadly weapon. One person was arrested for unlawful assembly, police said.

“What happened last night was disgraceful,” San Jose police Chief Eddie Garcia said Friday afternoon at a news conference.

Garcia said police will never condone violence and assaults are not a First Amendment right.

Garcia is forming a five-person task force to investigate the violence and police will be working with the Santa Clara County District Attorney to prosecute the people who were violent.

Garcia defended his officers who he said protected thousands of Trump supporters who went home safely.

When questioned by reporters about officers holding to their crowd control lines rather than breaking away and stopping acts of violence, Garcia said officers had to determine whether the act was a life and death

situation.

He said officers did not stop some acts of violence because arresting the perpetrators might cause more violence as protesters turned on police.

“That’s always a concern,” San Jose Police Officer’s Association spokesman Tom Saggau said.

When Garcia was asked what police could do differently next time, he said, “We would need more officers” with the goal of keeping more people from each other.

Garcia said about 250 officers were on duty for the event. “This was an all hands on deck” event, he said.

Saggau said San Jose does not have enough officers to handle an event such as Thursday’s rally.

A number of videos posted on social media showed violence between protestors and the business mogul’s supporters. Most of the violence took place at the end of the event, police said.

No significant property damage was reported.

But Saggau praised a separate peaceful protest held ahead of Trump’s rally. That protest was organized by a coalition of groups including Service Employees International Union Local 521 and the South Bay Labor Council.

That rally kicked off at about 5:30 p.m. a block from the convention center at Plaza de Cesar Chavez at 194 S. Market Street.

Protesters held signs that said “Trump leave San Jose” and “Do not forget who picks your food! Remember America was built by immigrants,” in response to Trump’s anti-immigration rhetoric.

SEIU Spokesman Stephen Boardman could not say how many union members were there, but said it was not a union-wide effort.

San Jose Mayor Sam Liccardo praised the work of police in a statement, saying, “San Jose police officers performed admirably and professionally to contain acts of violence and protect individual’s right to assemble, protest and express their political views.”

Liccardo is a supporter of former Secretary of State Hillary Clinton and he criticized the confrontational approach Trump has taken in his campaign, saying Trump has focused on stirring antagonism rather that offering real solutions to the country’s problems.

In social media posts, Trump characterized the protesters at the rally as “thugs” and “criminals.”

In a Twitter post at 5:43 a.m. Trump said the San Jose rally was “great.”

“Tremendous love and enthusiasm in the hall. Big crowd. Outside, a small group of thugs burned (American) flag,” Trump wrote.

Trump said at 6:30 a.m. on Facebook, “Thank you for the incredible amount of support last night — San Jose, California. I love you all — we will deal with the thugs & criminals — we will build the wall — and Mexico

will pay for it!”

Trump was last in the Bay Area in late April to speak at the California Republican Convention in Burlingame.

Protesters blocked the hotel where Trump spoke and the candidate had to traverse a ditch and enter the hotel through a back door. Five arrests and a minor injury were reported during the protest at the convention.

San Jose police are asking the public to submit any video or information they have that will help police arrest and prosecute the people who were violent.

Anyone with video to share has been asked to call (408) 537-4161 or 311. People who want to remain anonymous can call Crime Stoppers at (408) 947-7867 or go to https://www.p3tips.com/tipform.aspx?ID=504.

People can also file a crime report at http://www.sjpd.org/ReportingCrime/OnlineReport/.