The Allentown Police Department said officers responded to a parking lot in the 100 block of N. 7th Street at 6:46 p.m. after hearing gunshots.
According to police, the officers found several people actively shooting at each other.
In a press release, the Allentown Police Department said officers engaged the shooters, though no further details were immediately available about the actions taken by the officers.
Neighbors say you could hear the shooting from a block away.
"I live up the block from where the scene was at, and I was in my house when I heard the gunshots," said Nashley Reynoso.
Of the eight people who were shot, police say one of the victims required life-saving surgery.
The shooting happened as hundreds of people were gathered for the nearby Dominican Festival.
One person has been arrested so far.
Yunior Peralta Quintana, 21, of Bethlehem, has been charged with attempted criminal homicide, aggravated assault and related offenses.
Allentown police said the Lehigh County District Attorney's Office is assisting in the investigation.
Meanwhile, a local outreach organization was out at the scene on Monday afternoon with the hope of spreading their message of peace.
"We just got to do what we can together by coming together and advocating for safer gun laws and just advocating for violence prevention in general," said Zaleeae Sierra of Promise Neighborhoods of the Lehigh Valley.
Police are asking anyone with information to call detectives at 610-437-7721 or the Police Desk at 610-437-7753 ext. 1.