BIRMINGHAM, Ala. — Officials in Birmingham, Alabama, pleaded Monday with members of the public for information leading to arrests in a weekend shooting that killed four people and injured 17, announcing rewards totaling $100,000.

“I want to make myself very clear on what the priority is. It is to hunt down, capture, arrest and convict the people who are responsible for this mass shooting,” Mayor Randall Woodfin said at a news conference Monday with other officials.

Authorities have still made no arrests since the shooting late Saturday. Police described it as a targeted “hit” on someone by multiple shooters who opened fire on a crowd waiting in line outside a nightspot in the bustling Five Points South district.

Police believe that the shooters targeted at least one of the victims and that others were killed or injured in the barrage of gunfire, Chief Scott Thurmond said. Five of the injured victims remain in the hospital, he said. The FBI is offering a $50,000 reward, and Crime Stoppers is offering $50,000, officials said. Tipsters can remain anonymous.

The shooting — Birmingham’s third quadruple homicide of the year — has put a spotlight on a city once best known for its role in the Civil Rights Movement but more recently plagued by gun violence.

Three of the nation’s 31 mass killings this year occurred in Birmingham, according to a database maintained by The Associated Press and USA Today in partnership with Northeastern University. Birmingham, a city of about 200,000, has seen 114 homicides this year. Chicago, with more than 10 times the population, has seen a little over 400 homicides this year.

Saturday’s shooting rocked an area of restaurants and bars that is often busy on weekend nights. It occurred on the sidewalk and street outside Hush Lounge as a long line of people waited to enter. Bloodstains remained on the sidewalk until firefighters washed them away later Sunday.

Police identified the three victims found on the sidewalk as Anitra Holloman, 21, of the Birmingham suburb of Bessemer; Tahj Booker, 27, of Birmingham; and Carlos McCain, 27, of Birmingham. The fourth victim was identified Monday as Roderick Lynn Patterson Jr., 26.

Police recovered about 100 shell casings. In a statement late Sunday, police said the shooters are believed to have used “machine gun conversion devices” that make semiautomatic weapons fire more rapidly.

“We’re looking at whether the switch was used in this particular case, or was this an assault rifle that was fully automatic or some other type of weapon,” Thurmond said Monday.

The Birmingham mayor had urged state and federal officials to give cities more tools to address gun violence. He put his hands behind his back Monday to illustrate what it is like for cities to combat crime. Last year, Alabama abolished the requirement to get a permit to carry a concealed handgun in public.