CHICAGO>> The upbeat mood in a busy Chicago neighborhood known for its restaurants and nightlife quickly turned into horror late Wednesday as shots were fired at a crowd from a fast-moving vehicle, killing four people.

After the shots rang out, people who had attended an album release party for the rapper Mello Buckzz inside a nearby restaurant fell to the ground or screamed, witnesses said.

“I can only describe it as a war zone,” Chicago pastor Donovan Price, who responds to communities and people in crisis, told The Associated Press. “Just mayhem and blood and screaming and confusion as people tried to find their friends and phones. It was a horrendous, tragic, dramatic scene.”

Larry Snelling, superintendent of the Chicago Police Department, called the shooting a “cowardly act” at a Thursday news conference. He said the shooting was isolated to a location rented out for a specific event.

“In a matter of seconds, they were able to shoot 18 people, taking four lives,” he said.

Police said the driver immediately fled and no one was in custody. He asked the public to submit anonymous tips to help detectives identify suspects.

Police said 13 women and five men ranging in age from 21 to 32 were shot, and that the dead included two men and two women.

Snelling said police are trying to determine a motive and that the venue is closed “until we get to the bottom of this.” Snelling did not give an exact number of shooters but said police found two different calibers of casings and are still reviewing footage from the shooting.

“Clearly, there was some target in some way,” Snelling said. “This wasn’t some random shooting.”

The Cook County medical examiner’s office identified two of the victims who died as Leon Andrew Henry, 25, and Devonte Terrell Williamson, 23. The two women who died had yet to be identified Thursday morning.

At least three people were critically injured, police said. Those shot were taken to hospitals.

Price said people in the crowd outside Artis Restaurant and Lounge in the city’s River North neighborhood told him they had been at an album release party for a rapper. Videos on social media showed a red carpet outside and guests mingling and dancing inside.

Splattered blood and strewn belongings were still left on the sidewalk outside the restaurant Thursday afternoon.

The Black and LGBTQ-owned Creole restaurant, which opened in April, posted on Instagram that it was created as a safe space “where Black, Brown, Queer, and allied communities could gather, be celebrated, and feel at home in River North.”