At least four people were killed and more than 20 others injured, mostly teens, in a Saturday night shooting at a birthday party in Alabama, officials said, in the latest spasm of American gun mass violence.

Local news reports said the shooting occurred at a Sweet 16 party at a dance studio in Dadeville, a small town northeast of the state capital Montgomery.

“There were four lives tragically lost in this incident, and there’s been a multitude of injuries,” Sergeant Jeremy Burkett, a spokesman for the Alabama Law Enforcement Agency (ALEA), told reporters Sunday.

He specified later that 28 people had been wounded, some of them critically, and urged residents to come forward with any information they might have related to the attack. But Burkett provided no further details on how the shooting unfolded or why.

Annette Allen told the Montgomery Advertiser that her grandson Phil Dowdell was among those who died: he had been celebrating his sister Alexis’s 16th birthday when gunfire ripped through the party.

“He was a very, very humble child. Never messed with anybody. Always had a smile on his face,” Allen said of her grandson, a high school senior and football player due to graduate within weeks.

“Everybody’s grieving,” Allen said of the small community of some 3,000 residents.

President Joe Biden, who was briefed on the shooting, said the nation was again grieving over young Americans killed in gun violence.

“What has our nation come to when children cannot attend a birthday party without fear?” Biden, who has long sought tighter gun safety measures, asked in a statement.

“Guns are the leading killer of children in America, and the numbers are rising — not declining,” he added. “This is outrageous and unacceptable.”

The nearby Lake Martin Community Hospital received 15 individual gun-shot wound patients, mostly victims in their teens, Heidi Smith, marketing director for the rural health facility’s operator IvyCreek Healthcare, told AFP.

Six of the patients were discharged and nine have been transferred to facilities with higher levels of care. Of those, five were in critical condition, Smith said.

“It’s been terrible,” she said.

More than 12 hours after the tragedy, neither Burkett nor other law enforcement officials provided any details on who may have perpetrated the shooting and why, or whether a suspect has been detained.

“We can’t share anything further at this time,” the sergeant said, adding only that “it was tied to a birthday party.”

Dadeville Chief of Police Jonathan Floyd called the town “a tight-knit community full of wonderful people.”

The Alabama Law Enforcement Agency said its State Bureau of Investigations has launched a probe together with Dadeville police and federal agencies including the FBI.

Television station WRBL of nearby Columbus, Georgia reported heavy police activity overnight and crime scene tape around a building in Dadeville, where it said white sheets could be seen covering parts of the floor.

– ‘Heartbreaking’ –

State leaders took to Twitter Sunday offering prayers and decrying violence but they did not provide details on what happened.

“This morning, I grieve with the people of Dadeville and my fellow Alabamians,” Governor Kay Ivey posted. “Violent crime has NO place in our state.”

The United States, a country of around 330 million people, is awash with some 400 million guns, and deadly mass shootings are a regular occurrence.

The latest deaths came on the 16th anniversary of the deadliest US school shooting on record, in which 32 people were killed at Virginia Tech in 2007.

Separately, police confirmed two people were killed and four others wounded in a shooting late Saturday at a crowded park in Louisville, Kentucky, the same city where a bank employee slaughtered five people at his workplace last Monday.

There have been 163 mass shootings in the United States so far this year, according to the Gun Violence Archive. The non-profit group defines a mass shooting as having a minimum of four victims shot, either injured or killed, excluding any shooter.

Efforts to tighten gun controls have for years run up against opposition from Republicans, staunch defenders of the constitutional right to bear arms.

The political paralysis endures despite widespread outrage over recurring shootings.