In addition to those killed, four were wounded over the gunshots of a gunman, against several participants of a public meeting in the city of Ross Township, Monroe County, Pennsylvania.
The attacker, identified by the police as Rockne Newell, 59, was injured when an officer subdued him after shooting against about 15 people.
The state police Capt. Edward Hoke in a press conference said Newell apparently acted alone and everything began after he had a dispute with the local council on issues related to a sewer on his property.
United States suffers a wave of constant shootings, usually involving deaths. Last week in Miami, a man shot and killed several people, including a citizen from Ecuador. The shootings intensify the discussions about the freedom to bear guns among North Americans.