In addition to the four people whose lives were lost, 28 people were injured, some critically, during the shooting in east-central Alabama, about 60 miles (100 km) northeast of the state capital of Montgomery, authorities said.

Authorities said the shooting started shortly after 10:30 p.m. CT on Saturday but declined to answer questions or provide further details during two Sunday news conferences.

Officials would not even say whether a suspect has been killed or arrested, although they said there was no longer any threat to the community.

"We're going to continue to work in a very methodical way to go through this scene, to look at the facts, and ensure that justice is brought to bear for the families," said Jeremy Burkett, a sergeant with the Alabama Law Enforcement Agency.

The Montgomery Advertiser newspaper reported that one of the four people killed during the violence was a high school football player who was among those attending his sister's "Sweet 16" birthday celebration when a gunman opened fire.

The newspaper, quoting the victim's grandmother, identified the slain teenager as Phil Dowdell, who she said was set to graduate in a matter of weeks and planned to attend Jacksonville State University on a football scholarship.

Reuters could not independently confirm the information or learn the identities of the other three victims.

The party was being held inside the Mahogany Masterpiece Dance Studio, converted from an old bank building located about half a block from city hall in Dadeville, a town of about 3,000 residents. The scene was cordoned off with yellow crime-scene tape on Sunday.

Hundreds of community members gathered early Sunday evening in a parking lot a few blocks from the shooting scene for an outdoor prayer vigil.

The bloodshed in Alabama marked the third high-profile mass shooting in as many weeks in the U.S. South, following separate outbreaks of deadly gun violence in Tennessee and Kentucky that prompted local leaders to call for tighter gun control measures.

"What has our nation come to when children cannot attend a birthday party without fear?" President Joe Biden said in a statement on Sunday.

Biden called the rising gun violence in the U.S. "outrageous and unacceptable," and urged Congress to pass laws that would make firearms manufacturers more liable for gun violence, ban assault weapons and high-capacity ammunition magazines, and require safe storage of firearms and background checks for gun sales.

Tallapoosa County Schools Superintendent Raymond Porter said at the news conference that counseling would be provided at area schools on Monday, and asked local clergy to help families through the situation.

"We will make every effort to comfort those children and don't lose sight of the fact that those are the ones most impacted by this situation," Porter said.

Meanwhile, Republicans vying for their party's 2024 presidential nomination and other prominent party members sought to cast themselves as unwaveringly supportive of gun rights without restrictions in Indiana over the weekend at the annual conference of the National Rifle Association (NRA), the country's largest gun lobby.

The killings in Dadeville came five days after a bank employee shot dead five colleagues and wounded nine other people at his workplace in Louisville, Kentucky. On March 27, three 9 year olds and three staff members were killed at a private Christian school in Nashville, Tennessee, by a former student.

Mass shootings have become commonplace in the U.S., with more than 163 so far in 2023, the most at this point in the year since at least 2016, according to the Gun Violence Archive. The nonprofit group defines a mass shooting as any in which four or more people are wounded or killed, not including the shooter.