Originally Published: 04 JUL 22 23:35 ET

Updated: 05 JUL 22 09:51 ET

By Mark Morales, Liam Reilly, Amanda Jackson and Jessie Yeung, CNN

(CNN) -- Two police officers were shot during a July Fourth celebration in Philadelphia, authorities said.

A 36-year-old Philadelphia Highway Patrol officer suffered a graze wound to the forehead, and a 44-year-old Montgomery County Sheriff's deputy suffered a gunshot wound to the shoulder, according to Philadelphia Police Commissioner Danielle Outlaw.

Both officers were providing security at a July Fourth concert on the Benjamin Franklin Parkway when shots were fired around 9:47 p.m., just before the fireworks went off, Outlaw said.

Neither officer heard the gunshots before they were hit, she added.

"We don't know if this was ricochet from celebratory gunfire, we don't know if this was intentional," Outlaw said. "We're just extremely grateful this wasn't worse than it was."

The officers were taken to Jefferson University Hospital, treated and discharged, Outlaw said.

Social media video of the incident, apparently filmed from a nearby building, shows large crowds of people running along Benjamin Franklin Parkway, as lights from police cars and emergency vehicles flash in the street.

There have been no arrests so far, and no suspects in custody. Police said they are following several leads, and are asking members of the public to come forward if they have any information regarding the shooting or video capturing what happened.

Philadelphia Mayor Jim Kenney said the day had been "laid back, chilled," with good weather and an enjoyable concert.

"But we live in America, and we have the Second Amendment, and we have the Supreme Court of the United States telling everybody they can carry a gun wherever they want," he said. "This is what we have to live with."

Kenney, who was wearing a soccer jersey during the news conference, was asked about his concerns about the upcoming 2026 World Cup and other big events coming to Philadelphia.

"I'm concerned every single day," he said. "There's not an event or a day where I don't lay on my back at night look at the ceiling and worry about stuff. So everything we have had in the city over the last seven years, I worry about. I don't enjoy the Fourth of July. I didn't enjoy the Democratic National Convention. I didn't enjoy the NFL Draft."

"I'm waiting for something bad to happen all the time. I'll be happy when I'm not mayor and I can enjoy some stuff."

Kenney's second term as mayor is up in 2024.

"If I had the ability to take care of guns, I would. But the legislature won't let us, the US Congress won't let us," he added. "This is a gun country."