CHICAGO (AP) — Protesters rallied outside the Democratic National Convention on its opening day Monday, saying they were determined to voice their opposition to the war in Gaza and other issues. Chicago officials said they were committed to keeping the demonstrations peaceful.

Protesters said their plans have not changed since President Joe Biden left the race and the party quickly rallied behind Vice President Kamala Harris, who will formally accept the Democratic nomination this week. Activists said they were ready to amplify their progressive message before the nation's top Democratic leaders.

"We have to play our part in the belly of the beast to stop the genocide, to end U.S. aid to Israel and stand with Palestine," said Hatem Abudayyeh, a spokesperson for the Coalition to March on the DNC, which includes hundreds of organizations.

Mayor Brandon Johnson said authorities were well prepared. "The city of Chicago is really good at things like this," he told a news conference. "We are ready."

The Chicago area has one of the largest Palestinian communities in the nation, and buses were bringing activists from all over the country.

Organizers said they hoped the turnout for Monday's rally and march would be at least 20,000 people, but only a few thousand were there at the start of the march. City officials declined to give a crowd estimate.

Taylor Cook, an organizer with the Freedom Road Socialist Organization, traveled from Atlanta for the march. Cook said the group was pushing all Democrats to call for an end to aid to Israel, with a particular focus on Harris.

"We're saying to Kamala, she has been complicit in this. People think it's just Joe Biden, but she is vice president," Cook said. "So we're saying, you need to stop if you want our vote."

Medea Benjamin, who traveled to Chicago from Washington, D.C., with a women-led group of protesters calling for peace, said she was shocked that the Biden administration recently approved an additional $20 billion in weapons sales to Israel.

"There's an incredible discrepancy in what people are calling for in this country and what the administration is doing," she said ahead of the rally in Union Park. "We're so disgusted by this."

Activists say they learned lessons from last month's Republican National Convention in Milwaukee. They expect bigger crowds and more robust demonstrations in Chicago.

Pro-Palestinian supporters descended on the park, west of the Loop business district, for the rally. They planned to march a short distance to a site near the United Center, where the convention is taking place.

Independent presidential candidate Cornel West addressed the crowd, which welcomed him with cheers.

"This is not about some Machiavellian politics or some utilitarian calculation about an election," he yelled into a microphone. "This is about morality. This is about spirituality."

Around 40 pro-Israel supporters walked around the park during the rally. Remaining mostly silent while waving Israeli flags, they were accompanied by about 20 police officers on bicycles. Although tensions flared at times, there were no physical altercations.

Josh Weiner, co-founder of Chicago Jewish Alliance who walked with the pro-Israel group, said their intent was to "make our presence felt."

Weiner said the group applied for permits that were not approved by the city.

"The pro-Palestine protesters have gotten multiple permits, including a march, which seems to be a little bit weighted on one side," Weiner said.

Police Superintendent Larry Snelling praised police and march organizers for a peaceful Sunday night protest calling for abortion and LGBTQ+ rights and an end to the war in Gaza. Chicago police said two people were arrested on misdemeanor charges of resisting police and damaging property.

"Listen, it's this simple. The Chicago Police Department is here to protect everyone in this city," Snelling said. "What we will not tolerate is intimidation. We will not tolerate violence."

Protester issues include climate change, abortion rights and racial equality, to name a few, but many agree that pressing for an immediate cease-fire in the Israel-Hamas war is the top message of the demonstrations. They have likened it to the Vietnam War of their generation.

Chicago, which has hosted more political conventions than any other U.S. city, has been unable to escape comparisons to the infamous 1968 convention where police and anti-Vietnam War protesters violently clashed on live television.

Some businesses boarded up their windows as a precaution, and county courts said they would open more space in case of mass arrests. Chicago police say officers have undergone extensive training on constitutional policing and de-escalation tactics.

Coalition activists and the city have been at odds over the location of the protests and other logistics. A judge sided with the city over an approximately 1-mile (1.6-kilometer) march route, which organizers argue isn't big enough for the expected crowds. Abudayyeh said the coalition would continue to push for a much longer route.

Not a single speaker or spectator showed up by early afternoon to a speakers' stage offered by city officials near the United Center. Eight groups with progressive agendas had signed up for 45-minute speaking slots on Monday. On other days, some conservative groups, including the Illinois Policy Institute, have plans to speak.

Also Monday, the Philadelphia-based Poor People's Army, which advocates for economic justice, planned to set up at Humboldt Park on the city's northwest side to feature events with third-party presidential candidates Jill Stein and West, plus a 3-mile (5-kilometer) march.

"The First Amendment is fundamental to our democracy," Johnson, a former union organizer, told the AP in an interview last week. "I'll do everything in my power to protect the right to assemble in protest."