Philadelphia police say they responded to the incident just after 4 p.m.
According to investigators, a 34-year-old man went inside a booth in the park and laid down.
That's when the city park ranger reportedly told the suspect he wasn't allowed in the booth.
Police say the suspect then stabbed the city employee, who was overseeing security at Rittenhouse Square.
The 40-year-old victim suffered injuries to his face above his eye, according to police.
"He suffered a laceration to the face above the eye. Pretty serious injury," noted Inspector DF Pace with the Philadelphia Police Department.
The victim was transported to a nearby hospital and is listed in stable condition.
Authorities say people in the park witnessed the stabbing and grabbed the suspect after it happened. They reportedly held him down until police arrived at the scene.
"As you can see, there is a very large crowd of people usually here at the park throughout the weekend. A number of them grabbed the assailant until police arrived," said Pace.
Witnesses like Michelle Knoeppel from South Philadelphia said they heard a loud crash before they saw the suspect and victim fighting outside the booth.
"They come falling out of the doors onto the ground, the security guard has the guy's hand and won't let go of his hand. The security guard is bleeding, this guy will not let go at whatever is there," she recalled.
"I was just reading my book and I heard him yelling and screaming back and forth," added Terrence Hickman from Rittenhouse Square.
The suspect was later taken into custody by police. Officers say they recovered a pair of scissors at the scene, which they believe was the weapon used in the stabbing.
Investigators say this appeared to be a random attack. Even though there is no threat to the public, residents say they're concerned.
"It was alarming. Everybody knows the city has its issues with crime, but this area is known to be safer," said Brett Beilbelberg from Logan Square, who witnessed the incident.
The suspect is said to be undergoing a mental health evaluation.
No further information was released on this incident. There is no word yet on the suspect's identity.
Anyone with information is asked to contact the police.
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