PHILADELPHIA (AP) — Several hundred Bernie Sanders supporters and other demonstrators marched down Philadelphia's sweltering Broad Street on the opening day of the Democratic convention Monday, chanting "Nominate Sanders or lose in November!" and "Hey, hey, ho, ho, the DNC has got to go!"

The marchers made their way from City Hall toward the convention hall, 4 miles away in south Philadelphia.

Destine Madu, a protester from Maplewood, New Jersey, said it doesn't matter if Sanders is calling on his backers to support Hillary Clinton.

"He's like a Moses," she said. "He led us to the promised land."

The protests took shape amid a punishing heat wave, with oppressive humidity and temperatures in the mid-90s, along with the possibility of severe thunderstorms in the evening. The Fire Department handed out bottled water, and at least one woman was put in an ambulance by stretcher.

The demonstrators espoused a variety of causes, including economic justice, socialism and marijuana legalization. With Sanders out of the race, some of them were backing Green Party candidate Jill Streen.

Although planned for months, the marches came as fissures widened in the party. Debbie Wasserman Schultz resigned Sunday as Democratic Party chairwoman over leaked emails suggesting the supposedly neutral Democratic National Committee played favorites for Clinton during the primaries and bad-mouthed Sanders.

About 100 Sanders supporters made their way into Philadelphia by marching across the Ben Franklin Bridge from Camden, New Jersey. Among them was Jim Glidden, a salesman from Batavia, New York. He carried a big sign saying the DNC stands for "Dishonest Nefarious Corrupt."

"Only one guy is telling the truth out there," he said, referring to Sanders. "And the DNC shut him up with lies and cheating."

Another participant in the bridge march, Deborah Armstrong, of Spokane, Washington, said she and her husband went bankrupt because of his health problems, which required a heart transplant.

"I'm Bernie or bust," she said. "I'm not going to have Trump held up to our head like a gun."

Philadelphia Police Commissioner Richard Ross was again on scene of the protests, watching as he did on Sunday as officers directed traffic and kept protesters confined to the sidewalks.

Ross said that Sunday's marches involving thousands of people were "like a scrimmage game" and that while the protests will only get bigger, he was pleased with how respectful the demonstrators have been.

Protest organizers have been thanking police and urging demonstrators not to litter. But tensions rose Monday when about 50 marchers sat on the street and refused to move unless a Mississippi flag with the Confederate emblem was taken down from a lamppost.

Two officers stood in front of the lamppost, not allowing anyone to climb it, as hecklers jeered: "Think for yourself. Be a real man."

The four-day convention is being held at the Wells Fargo Center, well removed from City Hall and the skyscrapers of Center City.

By contrast, the Republican convention last week in Cleveland was held in a bustling part of the city. A heavy police presence and fewer than expected protesters helped authorities maintain order. Only about two dozen arrests were made.