BIRMINGHAM, Ala, Sept 23, (AP): Authorities have reported no immediate arrests after a weekend mass shooting killed four people and left 17 others injured in what police described as a targeted "hit” by multiple shooters who opened fire outside a popular Alabama nightspot. The shooting late Saturday night in the popular Five Points South entertainment district of Birmingham, rocking an area of restaurants and bars that is often bustling on weekend nights.

The mass shooting, one of several this year in the major city, unnerved residents and left officials at home and beyond pleading for help to both solve the crime and address the broader problem of gun violence. "The priority is to find these shooters and get them off our streets,” Birmingham Mayor Randall Woodfin said a day after the shooting.

The mayor planned a morning news conference Monday to provide updates on the case. The shooting occurred on the sidewalk and street outside Hush, a lounge in the entertainment district, where blood stains were still visible on the sidewalk outside the venue on Sunday morning. Birmingham Police Chief Scott Thurmond said authorities believe the shooting targeted one of the people who was killed, possibly in a murder-for-hire.

A vehicle pulled up and "multiple shooters” got out and began firing, then fled the scene, he said. "We believe that there was a ‘hit,’ if you will, on that particular person,” Thurmond said. Police said approximately 100 shell casings were recovered. Thurmond said law enforcement was working to determine what weapons were used, but they believe some of the gunfire was "fully automatic.” Investigators also were trying to determine whether anyone fired back, creating a crossfire. In a statement late Sunday, police said the shooters are believed to have used "machine gun conversion devices” that make semi-automatic weapons fire more rapidly.