Alabama mass shooting: Four dead and 18 injured after 'multiple gunmen' open fire in Birmingham

At least four people are dead and 18 are injured after gunmen opened fire on a crowd in Birmingham, Alabama .

Multiple gunmen shot at a crowd on 20th Street near Magnolia Avenue in Birmingham's Five Points South area at around 11pm on Saturday.

Two men and a woman were found dead at the scene. A fourth victim succumbed to gunshot wounds in hospital.

By early Sunday, police had identified 18 other victims with injuries, some of them life-threatening.

Police are probing whether the killers approached on foot or in a drive-by assault.

No arrests have been made and investigators have not yet determined the intended targets.

The Five Points South area of Birmingham has numerous entertainment venues, restaurants and bars and often is crowded on Saturday nights, news outlet WBMA reported.

"We will do everything we possibly can to make sure we uncover, identify and hunt down whoever is responsible for preying on our people this morning," Birmingham Officer Truman Fitzgerald told WBMA.

"Detectives believe the shooting was not random and stemmed from an isolated incident where multiple victims were caught in the crossfire," he said.

Streets have been blocked off in the area as police continue to investigate.

Fitzgerald said police have reached out to the FBI and ATF for assistance

The Gun Violence Archive reports over 400 mass shootings in the US this year, defining them as incidents where at least four people are shot or killed.