WASHINGTON, April 16 (Reuters) - At least four people were killed and 28 wounded in a shooting that erupted during a late-night "Sweet 16" birthday celebration at a dance studio in the small town of Dadeville, Alabama, state police and local news media said on Sunday.

Some of the injured were critically wounded during the shooting in east-central Alabama, about 60 miles (100 km) northeast of the state capital of Montgomery, authorities said. There was no official word on what led to the gun violence.

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

Officials said there was no longer any threat to the community but did not say whether a suspect has been killed or arrested.

"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 party when a gunman opened fire.

The newspaper, quoting the victim's grandmother, identified the slain teenager as Phil Dowdell, whom 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 3,200 residents. The scene was cordoned off with yellow crime-scene tape on Sunday.

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