The chaos unfolded near the intersection of Belle Avenue and West 7th Street on Sunday afternoon.
All of the victims were teenage boys.
Schools in the area were closed due to the shooting, Delaware News Journal reported.
Police warned at 3.20pm that the area was not secure and multiple suspects remained at large.
Members of the public were warned to stay away from the area, according to a string of messages posted by Delaware State Police on X, formerly known as Twitter.
“This is believed to be an isolated incident,” the statement read.
“Please continue to avoid the area as there continues to be a large police presence while the investigation is conducted. There is no suspected threat to the publice.”
Delaware State Police have been contacted for comment.