Supporters of Democratic presidential candidate Bernie Sanders react as U.S. Sen. Barbara Boxer, D-Calif., speaks during the Nevada Democratic Party convention on Saturday, May 14.

Supporters of Democratic presidential candidate Bernie Sanders react as U.S. Sen. Barbara Boxer, D-Calif., speaks during the Nevada Democratic Party convention on Saturday, May 14. Photo: Chase Stevens/Las Vegas Review-Journal/Associated Press

Philadelphia has approved four demonstration permits in support of Sen. Bernie Sanders at the July Democratic National Convention — including a large rally planned near the convention's epicenter.

One of the permits is for an event consisting of four days of all-day rallies at FDR Park in support of Mr. Sanders. The city said it expects 30,000 participants, and organizers said in an interview they hope turnout will be much higher.

The park is adjacent to the Wells Fargo Center, where many of the Democratic National Convention events will be held — raising the possibility of a large demonstration in support of Mr. Sanders just steps away from where delegates will officially select the Democratic nominee. A growing number of Democrats are concerned the convention could turn out to be divisive and disorderly due to activities planned by Sanders supporters.

The city has also granted permits to three smaller demonstrations at Thomas Paine Plaza, a few miles from the Wells Fargo Center. The city says it expects 2,000 to 3,000 participants at those events.

The events — which are being organized independent of campaign by supporters of Mr. Sanders — aim to call attention to support the Vermont Senator has received throughout the primary process and push for long-term changes in the way that the Democratic Party nominates candidates.

"The whole Bernie movement is an ideology. If Bernie wins the nomination, wins the presidency, that would be amazing. But even if Hillary does win the nomination, the movement has already started," said Steve Okan Layne, who is helping organize one of the demonstrations.

The size, scope and tenor of the events at the convention depend in part on Mr. Sanders himself. Mrs. Clinton has a substantial lead in the delegate count and is likely to clinch the nomination with the declared support of superdelegates before the convention.

If Mr. Sanders is looking to maximize his influence at the convention, he could encourage supporters to show up at the convention to make their voices heard on issues like the party platform and future rules.

After a chaotic state convention in Nevada where supporters of Mr. Sanders disrupted the event and threatened the state party chairwoman, some Democrats have begun to fear that the Philadelphia convention could potentially be a messy event with a potential for violence.

Organizers say they are working with the city to keep the demonstrations peaceful and constructive.

"We are marching. If you're planning on coming here with violence in mind, we don't want you," said Bill Taylor, one of the organizers.