CHICAGO (AP) — Multiple pro-Palestinian demonstrators were arrested Tuesday after clashing with police during a protest that began outside the Israeli consulate and spilled out onto the surrounding streets on the second night of the Democratic National Convention.

The intense confrontations with officers began minutes into the demonstration, after some protesters – many dressed in black, their faces covered – charged at a line of police that had blocked the group from marching. They eventually moved past the officers, but were penned in several times throughout the night by police in riot gear who did not allow protesters to disperse.

The Chicago chapter of the National Lawyers Guild, which provided legal observers for Tuesday’s protests, said at least 72 people were arrested.

A large portion of the arrests happened at the end of the night, as police pinned the remaining demonstrators – some of whom said they were trying to get home – in a plaza and blocked them from leaving. Police Superintendent Larry Snelling denied that police had “kettled” protesters, a tactic that involves corralling demonstrators in a confined area, which is banned under a federal consent decree.

Snelling, who has been present at all major demonstrations during the convention, praised his officers’ handling of the protests, calling the response proportional.

“We have people who showed up here to commit acts of violence,” he told reporters late Tuesday. “They wanted chaos.”

When asked to detail the violent acts, he said the demonstrators walked right into police officers. He declined to give the number of arrests, saying he did not have a final total.

Earlier in the evening, some demonstrators set an American flag on fire in the street as the celebratory roll call for Vice President Kamala Harris took place inside the United Center about 2 miles (3.2 kilometers) away.

As protesters regrouped and approached a line of police in riot gear in front of a Chicago skyscraper that houses the Israeli consulate, an officer said into a megaphone, “You are ordered to immediately disperse.” A woman in the front of the march shouted back with her own megaphone: “We’re not scared of you.”

A man in Chicago Bulls hat, his face covered by a balaclava, called on protesters to “shut down the DNC.” The group, which is not affiliated with the coalition of over 200 groups that organized Monday’s protests, advertised the demonstration Tuesday under the slogan of “Make it great like ’68,” invoking the anti-Vietnam War protests that seized the city during the 1968 Democratic National Convention.

The atmosphere with rows of police in riot gear was a stark contrast to a day earlier when thousands of pro-Palestinian activists, including families pushing babies in strollers, marched near the convention site calling for a ceasefire.

Police kept protesters confined to a block of Madison Street, a normally bustling downtown thoroughfare where traffic was halted on both ends Tuesday evening.

Law enforcement had closed down most of the entrances to the building on Tuesday, allowing commuters to come in only one entrance where armed officers were also posted. Many of the building’s shops were closed. Martha Hill, a spokeswoman for the Metra commuter rail service, said train service was running as normal.

The consulate has been the site of numerous demonstrations since the war in Gaza began in October. It is in a building connected to the Ogilvie Transportation Center, a major commuter rail station.

Mohammed Ismail, a 29-year-old psychiatry resident who lives in Chicago, described the police presence as “excessive,” and questioned why the group had been blocked from marching. He said he joined the protest to urge Democrats to cease funding to Israel.

“It’s not right that we’re sending our tax money to fund an ongoing slaughter, an ongoing genocide,” Ismail said. “We’re a part of this conflict because our money is paying for it.”

Meanwhile, the sites of demonstrations from the previous night were largely quiet. Thirteen people were arrested during Monday’s protests, most them related to a “brief breach” of security fencing “within sight and sound of the United Center,” Snelling said.

Israel supporters, including some relatives of people kidnapped by Hamas, gathered earlier in the day at a pro-Israel art installation not far from the consulate to call on U.S. leaders to continue backing Israel and pushing for the release of hostages. The art installation included giant milk cartons bearing photos of some of the hostages.

Elan Carr, CEO of the Israeli-American Council, condemned the pro-Palestinian protesters who have descended on Chicago this week, calling them “fringe crazies” and demanding that U.S. leaders “stand unequivocally with the state of Israel.”

More protests were planned throughout the week. However, attendance at the main rally on Monday was far below estimates of organizers who had predicted more than 20,000 would show up.

Snelling said Monday’s crowd was around 3,500 people and that the vast majority of those protesters were peaceful.