Several protesters briefly broke through a security gate outside of the Wells Fargo Center just before President Barack Obama addressed Democratic National Convention attendees inside the arena.
Philadelphia Police said they detained seven people who breached the fence at Broad Street and Pattison Avenue. The Secret Service arrested the seven and said they faced felony charges for entering a restricted area. The protesters didn't enter the Wells Fargo Center, said authorities.
Police Commissioner Richard Ross said protesters were warned repeatedly not to breach the area.
"For whatever reason, they chose to do it anyway with multiple officers sitting there waiting for them, so it was over before it started," Ross said, explaining the situation never got tense for the officers, who were still in "soft" clothes rather than protective gear. "We're just not gonna let anything get out of hand," Ross said, adding that 99-percent of the people were not an issue, only a handful of instigators.
Officers secured the fence and the crowd calmed down.
Separately, a woman was injured while trying to put out a flag that was set on fire, according to NBC News. She was treated at the scene for burns on her leg.
One police officer suffered non-life-threatening injuries trying to stop someone from cutting into a fence at Broad and Geary streets -- slightly north of the arena, said Philadelphia Police.
Philadelphia Police turned the arrested protesters over to the Secret Service who took them to the city's Federal Detention Center for arraignment, said the Secret Service.