The air strikes and rocket fire this week represent the first major escalation since Israel's invasion of Gaza in late 2008.
Israel says it is responding to Hamas rocket fire. Palestinians accuse Israel of strikes at Hamas leaders that also have killed civilians.
"We're here because there's no other way to get the word out. There's no one backing Palestine," said Hanan Kayed, 31, a Philadelphian of Palestinian descent. "In a way, we all feel helpless. There's not much we can do."
Across the street, Drexel University undergraduate Shoshana Weiss, 21, of Cherry Hill, said she came because of the current violence, but the conflict is more fundamental.
"If you read an article, you assume it escalated from Wednesday. But in reality, it escalated from a decade ago," Weiss said. "If you really understand facts, you would understand why the American government supports Israel. And as an American and with American values, I have to support them."
The America-Israel link was acknowledged by the demonstrators.
"America stands for Israel," pro-Israel demonstrators chanted, to a quick response from the Palestinian supporters: "Israel and U.S.A., how many kids have you killed today?"
The rallies were peaceful, with both sides chanting, singing, and sometimes trading verbal jabs. But standing on either side, the chants from across the street were often hard to understand. Often they were similar - "Stop the rockets, there will be peace," shouted the pro-Israel demonstrators; "No more air strikes," called the Palestinian ralliers.
And in one striking moments, both sides shared the same rallying cry.
A few from the Israel side began chanting, "Peace, not war," and the rest of the group began to pick it up. Then, pro-Palestinian voices began the same refrain.
Suddenly, for a brief moment, both sides were chanting loudly at each other, "Peace, not war!"
Within a few beats, it was over, with both sides exchanging accusations once again.
Contact Jonathan Lai at 215-854-2771, firstname.lastname@example.org, or on Twitter @elaijuh.
Inquirer staff writer Michael Matza contributed to this article.