The shooting broke out at the Wawa Welcome America concert on the Benjamin Franklin Parkway around 9:45 p.m., Philadelphia police said.
In viral videos shared on Twitter, attendees could be seen frantically running away from the scene as the fireworks display continued.
The officers were serving as security detail in front of the Philadelphia Museum of Art when the shots rang out on the 2500 block of Spring Garden Street, authorities said.
Outlaw said they did not hear any shots fired.
"The first officer was a PPD highway patrol officer who suffered a graze wound to his forehead and the second officer who was assigned to the Montgomery County Sherriff's Office Bomb Squad Task Force, suffered a graze wound to the right shoulder," Police Commissioner Danielle Outlaw said at a press briefing.
Both victims were taken to Jefferson Hospital and released early Tuesday morning, authorities said.
The Philadelphia police officer has been identified as 36-year-old Sergio Diggs, a 13-year veteran of the department, police said.
The officer with the Montgomery County Sheriff's Office was identified as 44-year-old John Foster.
Foster is a 17-year veteran of the MCSO and has been a member of the bomb squad for three years, the sheriff's office said on Facebook.
Following the shots, police were directing crowds away from the area and asking people to meet their loved ones in front of the city's public library on Vine Street.
"I'm waiting for something bad to happen all of the time," Philadelphia Mayor Jim Kenney told NBC10.
"I can’t enjoy large events because I fear what could happen" and "I'll be happy when I'm not [the] mayor and can enjoy some stuff."
The gunman remained at large as of Tuesday, authorities said.
Anyone with information on the incident is asked to contact the Philadelphia Police Department at (215)-686-TIPS
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