Protesters gathered again Sunday outside a national law enforcement event at the Pennsylvania Convention Center, following a march Saturday in which two demonstrators were arrested and charged with assaulting Philadelphia police officers.

The Sunday demonstration stayed peaceful, resembling a lecture more than a protest. About 40 protesters gathered at 12th and Arch Streets for nearly two hours, listening to several speakers talk about police brutality and racial profiling.

The speakers called for police departments to be abolished, saying that officers regularly violate people's rights and that police in general are a waste of money.

"We don't talk to pigs of any sort. In any uniform," one speaker, a young woman who declined to provide her name, told the crowd. Another speaker called police "rotten to the root."

The demonstrators, mostly young people, handed out fliers to passersby and held signs that read, "White silence is violence" and "No good cop in a racist system."

About 30 police officers stood across the street from the demonstration, keeping an eye on it.

Philly for REAL Justice, a group that marches against police brutality, organized both demonstrations through Facebook. Saturday's demonstration, which started at the Convention Center and continued down Center City streets, was largely peaceful until the group of about 50 protesters clashed with police near the controversial statue of the late Mayor Frank L. Rizzo.

Police reported Saturday that two officers and a protester suffered minor injuries.

The demonstrations come as thousands of law enforcement officials meet in Philadelphia at a conference for the Major Cities Chiefs Association and the International Association of Chiefs of Police. U.S. Attorney General Jeff Sessions addressed the conference Saturday and is expected to make another appearance Monday, when he will make an announcement on plans to combat the violent gang MS-13, the Department of Justice announced Sunday. The conference will end  Tuesday.

A man who was attending the conference walked up, an ice cream cone in one hand and his camera in another. He attempted to record the protesters. Immediately, a protester jumped up to block his camera. This went back and forth for a minute until he walked away.

Here is a sampling of the Sunday protests, which began around 2:30 p.m.:

Sofiya Ballin contributed to this article.