At least four people have been killed and 18 injured in a mass shooting in Birmingham, Alabama, police say.

“Multiple shooters fired multiple shots on a group of people” late on Saturday in the Five Points South area of the city, Birmingham police officer Truman Fitzgerald said.

Police found the bodies of two men and one woman at the scene and a fourth victim died of bullet wounds in hospital, he said.

Detectives are investigating whether the gunmen walked up to the victims or drove by, Mr Fitzgerald added. No suspects have been arrested.

The Five Points South district is known for its nightlife. The shooting occurred on Magnolia Avenue, Mr Fitzgerald said.

Witnesses who were queuing outside a hookah and cigar lounge on Magnolia Avenue at the time told local news site Al.com that some of the gunfire sounded as though it came from a gun converted to be fully automatic.

Speaking about the injured, Mr Fitzgerald told reporters: “We have dozens of gunshot victims from this area. I’m told at least four of those gunshot victims are life-threatening.”

There have been more than 400 mass shootings across the US so far this year, according to the Gun Violence Archive, which defines a mass shooting as an incident in which four or more people are injured or killed.