The protesters gathered outside of a planned event at the Rittenhouse Hotel that Vice President Mike Pence headlined, a Republican fundraiser with Pennsylvania gubernatorial nominee Scott Wagner.
Many protesters carried signs decrying the Trump administration's "zero tolerance" policy on migrants that has resulted in the separation of parents and children.
Refusing to back down on his stance, the President has blamed Democrats, but demonstrators say this isn't a political issue but rather a humanitarian one.
"This isn't a party issue, it's unacceptable," said Jade Contra, protest organizer.
Organizers arranged about 50 pairs of children's shoes into the word "No" on the walkway facing the Rittenhouse Hotel.
"The shoes symbolize these kids in need," said demonstrator Mark Timkleman. "They are missing and they don't have a voice out here."
Organizers say the shoes will be donated to charity following the rally.
Throngs of people, many of whom came to the downtown park after work, continued to arrive well after the start of the rally.
Police officers had shut down streets on two sides of the park to restrict access to the hotel where Pence was speaking.
Things turned tense when a Secret Service agent assigned to Pence's detail tried to leave by driving through a crowd of protesters on Walnut near 19th Street.
Update from @PhillyPolice. It was a @SecretService agent parked on Walnut that tried to leave the area. He turned his lights and sirens on and slowly drove towards of crowd of protestors, expecting them to move. pic.twitter.com/GcuJn7bjdr— Christie Ileto (@Christie_Ileto) June 19, 2018
"He activated his emergency equipment and was trying to get through a crowd," said Philadelphia Police Capt. Sekou Kinebrew. " Several protesters surrounded the vehicle, bike officers intervened, and when that happened someone jumped on the Secret Service vehicle. That person has been detained."
One protester said things sometimes get out of hand when people are upset.
"When people are this angry that children are being taken away from their families, that's what you get," said Mary Anne Duffy.
Send a News Tip to Action News
Learn More About 6abc Apps