The suspect, a man believed to be aged 40, did not appear to have any connection to the victims, police said.
Four people have been killed in a mass shooting in Philadelphia overnight and a suspect has been taken into custody, according to the local police, in the latest outbreak of gun violence in the United States.
The gunman wearing a bulletproof vest opened fire on the streets on Monday night over several city blocks in the southwestern neighbourhood of Kingsessing before responding officers chased the suspect.
No connection was immediately known between the victims and the shooter, identified as a 40-year-old man.
“At this point, all we know is that this person decided to leave their home and target individuals,” Police Commissioner Danielle Outlaw said at a news conference.
He had a bulletproof vest, an “AR-type rifle,” multiple magazines, a handgun and a police scanner, she said.
A second person was also taken into custody who may have returned fire at the suspect, but police did not know whether there was a connection between the two people, Outlaw said.
The chief described the scene as covering an area of two by four blocks and said dozens of shell casings were found.
“We’re canvassing the area to get as much as we can, to identify witnesses, to identify where cameras are located and to do everything to figure out the why,” Outlaw said.
Three of the dead ranged in age from 20 to 59, while the fourth, who had not yet been identified, was estimated to be aged between 16 and 21. All were male.
The two hospitalised victims are boys, ages two and 13. They are in stable condition, Outlaw said.The shooting occurred a day after gunfire erupted at a holiday weekend block party in Baltimore, about 160km (100 miles) to the southwest, killing two people and wounding 28 others. The wounded in that shooting ranged in age from 13 to 32, with more than half of them minors, according to officials.
The Philadelphia violence marks the country’s 29th mass killing in 2023, according to a database maintained by The Associated Press and USA Today in partnership with Northeastern University.
The US has witnessed the highest number on record of mass killings and deaths to this point in a single year.
There have been more than 550 mass killings since 2006, according to the database, in which at least 2,900 people have died and at least 2,000 people have been injured.