CHICAGO (CBS) — A total of 13 people were arrested during the first day of the Democratic National Convention in Chicago, police said, including about 10 people who were arrested after a small group of agitators breached the outer security perimeter fence outside the DNC during a much larger protest march.

Chicago Police Supt. Larry Snelling estimated 3,500 protesters marched from Union Park, a few blocks away from the United Center, to Park 578 just north of the arena, before returning to Union Park on Monday afternoon, and the vast majority of them remained peaceful.

The protest was a show of solidarity with Palestine, with activists calling for a ceasefire in Gaza, and an end to U.S. funding to Israel.

Snelling said a small group of agitators within the larger protest crowd removed locks from some of the outer fencing around the United Center, and knocked down part of the outer security fence around 4:30 p.m., and some people passed through a gap in the fence, and began trying to knock down a second layer of fencing, but police were able to stop them.

“It was a brief breach,” Snelling said.

Snelling said some of the people who got past the outer fence threw water bottles and other objects at police, and some in the crowd sprayed officers with pepper spray. The officers suffered only minor injuries.

“We’re not going to tolerate vandalism and violence in our city, and we’re ready, willing, and able to respond to those things. So we’re going to continue to protect the city,” Snelling said. “I couldn’t be more proud of how the Chicago Police Department responded under those circumstances. We put on display the training and the preparation that we’ve been engaged in for over a year now.”

A total of 13 people were arrested on Monday in connection to the DNC. Snelling said approximately 10 of those people were arrested in connection to breaching the security fence, and would face charges including trespassing, resisting and obstructing police, and aggravated battery of police officers.

“Our officers did not overreact. We were able to clear that area up really quickly,” Snelling said.

Snelling said the security perimeter around the United Center has since been fortified to make sure there aren’t any more breaches during the DNC. Crews were seen adding an extra layer of fencing to the security perimeter near the United Center on Tuesday morning.

U.S. Secret Service Democratic National Convention Coordinator Jeff Burnside declined to discuss details of any other changes that have been made along the security perimeter, but confirmed that other repairs have been made to the security fence.

“We take a multi-layered approach to all of our security measures, and we’re constantly working with our state, local, and federal partners to evaluate, make improvements, make adjustments, and that’s all we’re doing,” Burnside said. “Our plan was in place, our plan worked. We’re taking some lessons learned, and making the necessary adjustments.”

The Chicago chapter of the National Lawyers Guild said two of the people who were arrested on Monday were hospitalized, and claimed police assaulted them, but Snelling denied that, insisting the two were taken to the hospital to get medication they needed.

“Those police officers responded perfectly, and we’ve got body cam footage to prove it. They were not hospitalized for injuries. As a police department, anytime we take someone into custody, if they’re on medication or the need medication, we make sure they get that,” Snelling said.

Despite the breach of the fence, Snelling said there was no need for CPD to change its public safety strategy during the DNC.

“We can’t account for every situation that could happen, but if we respond to it, and we put an end to it before it turns bad, then we’ve done our jobs,” he said.

Snelling said, while the vast majority of the people involved in Monday’s protest march were peacefully exercising their First Amendment rights, a small group decided to stay behind after the protest began leaving the area and breached the fence.

“The people who decided that they wanted to commit crimes and vandalism stayed behind. We responded to that event with our officers who were properly trained to deal with the situation, and as a result of it there was no serious breach that could have been worse had we not been prepared for that,” he said.

Snelling said he believes the officers who responded to the breach of the fence showed proper restraint while making arrests.

“The officers could have used more force in situations yesterday than they actually did, and those officers showed great restraint. We’re always going to have opposition to our response. There are people out there who don’t believe we should even exist. So of course we’re going to have those who are going to say that we were too aggressive,” he said.

The superintendent said police would release body camera footage of Monday’s arrests as soon as possible after those who were arrested are formally charged.

Snelling dismissed claims from the National Lawyers Guild that two of the people who were arrested claimed they were simply in the wrong place at the wrong time.

“Sometimes being in the wrong place at the wrong time is indicative of the choices that you make to engage in criminal activity,” he said.