New Jersey State Police said a 30-year-old man and a 25-year-old woman died in the shooting. Police have not released the victims' name. Family members, however, identified the 25-year-old victim as Asia Hester.
One of the 12 people who were injured is in critical condition. All of the victims were adults, according to investigators.
Six of the victims were rushed to Cooper University Hospital Sunday morning. Hospital officials told Action News that two victims were released while four others remain hospitalized for more serious injuries.
No arrests have been made. State police said the motive remains under investigation.
Officers were called to a home on E. Commerce Street in Fairfield Township, Cumberland County around 11:50 p.m. Saturday.
More than 100 people were at the home for a party at the time, officials said.
Residents said the trouble started when people from a neighboring party showed up to the home. That's when rapid gunfire rang out, they said.
Neighbors said they heard popping noises that sounded like fireworks
"We started seeing cops flying down the road, state troopers coming down this way, helicopters in the air and I'm like, 'This is nuts, man,'" recalled Joeron Pierce, who lives nearby.
Chopper video showed the aftermath on Sunday morning. A tent that appeared to have been knocked over was on the ground. Debris was scattered around the yard.
Cars were parked all along the street, and police said some were parked blocks away.
Police began searching a large area around the home, including nearby woods and a cemetery.
The uncle of one of the victims was at the scene. He said his niece was a "good girl" and he was "absolutely heartbroken."
MASS SHOOTING in Fairfield Twp, Cumberland County. Police say someone started shooting at a house party with hundreds of people in attendance. Multiple people shot, some did not make it. @6abc pic.twitter.com/lR9qFVSfZB— Beccah Hendrickson (@Beccah6abc) May 23, 2021
Police said some of the wounded victims were taken to the hospital by medics, while others drove themselves.
John Fuqua, of the Life Worth Living organization, said his nephew's friend was among those who were shot.
"He was running for his life. He got on the ground, he had to crawl," Fuqua said. "It wasn't a shooting gallery, it wasn't a hunting expedition, it was a party and a few bad apples chose to turn it into something else."
Rev. Michael Keene of the Trinity AME Church heard the gunfire. The church which sits right across the street from the shooting scene.
"I just started hearing at first what I thought was fireworks, it was really gunshots, and I heard nine in rapid succession," said Rev. Keene.
Community leaders said the gathering was a 90s-themed birthday party and was attended mostly by young people.
"We have a lot of challenges in this community and we've had a lot of tragedies," said Melissa Helmbrecht of the HopeLoft Community Center.
Helmbrecht said the partygoers were excited about the warm weather and opportunity to get together.
"I'm just worried for our friends, our family, our employees. Over the coming days we're going to have a lot of pieces to put back together," she said.
"If you're going to a party, why do you need to take a gun?" asked Keene. "If you're there to have a good time ,why do you need a gun with you? That means you're expecting trouble to me."
Fuqua said it will take the efforts of the entire community to help.
"This ain't a sit back on the sideline and watch activity, this is about boots on the ground. You've got to get on the floor, you've got to get your knees a little bit dirty if we want to clean up our community," Fuqua said.
Community leaders decided to proceed with their scheduled youth basketball game Sunday afternoon, seeing it as an outlet after what happened.
"It looks like it's the best thing to do so that these young people can burn off some steam, get their frustration out. We have grief counselors here, so we can get through this. It's not going to be easy but we're going to get through this," said Bridgeton Mayor Albert Kelly.
Fairfield Township Mayor Benjamin Byrd Sr., who was at the scene Sunday, said that New Jersey Gov. Phil Murphy offered his support and help.
"Nobody knows when someone's going to come out of the woods with a gun," Byrd said. He did not have any details about the shooting.
In a statement released Sunday, Gov. Murphy expressed gratitude for the efforts of law enforcement and first responders while condemning the violence.
"Let there be no mistake: This despicable and cowardly act of gun violence only steels our commitment to ensuring New Jersey leads the nation in passing and enforcing strong and commonsense gun safety laws," Murphy said. "No community should ever experience what occurred last night in Fairfield."
Gov. Murphy, State Police Superintendent Colonel Patrick Callahan and Cumberland County Prosecutor Jennifer Webb-McRae are scheduled to provide an update on the mass shooting Monday morning.
-- The Associated Press contributed to this report.