Officers responded shortly after 11 p.m. to a report of multiple people shot outside a nightclub, Birmingham Police Department Officer Truman Fitzgerald said in a video posted on social media.

Birmingham Fire and Rescue personnel pronounced one man dead on a sidewalk near the nightclub. Two women were killed inside the club, Fitzgerald said.

A second man was pronounced dead at University of Alabama at Birmingham Hospital, where at least nine additional victims were being treated for gunshot wounds, he said.

Victims were brought by emergency medical personnel or traveled to the hospital on their own, Fitzgerald said.

Investigators believe at least one suspect fired shots into the nightclub from the street, he said. Federal law enforcement authorities were assisting Birmingham police with the investigation.

Separately, police responded around 5:20 p.m. to a report of a vehicle accident in Birmingham. Police found a car that appeared to have been shot into located in the front yard of a home, Fitzgerald said.

Inside the vehicle were a man, woman and a small boy who had suffered gunshot wounds. Birmingham Fire and Rescue pronounced all three dead at the scene, he said. They were identified by police as a 28-year-old woman from Center Point, Alabama, and her child, 5. Also killed was a 28-year-old man from Hoover, Alabama, who is believed to be the mother's boyfriend, police said.

Investigators believe they were victims of a "targeted shooting” before the suspect fled in a vehicle, Fitzgerald said.

Birmingham Mayor Randall Woodfin said Sunday on social media that it was authorities' priority to find the people “who committed these heinous acts.”

“We need swift justice for the victims and their families,” Woodfin said. “The shooter/shooters deserve no safe harbor from their own family, friends, or strangers. Do not protect them.”

Police asked area residents to provide footage from home surveillance cameras to assist the investigation.

In a statement Sunday morning, Birmingham police said they “remain resolute in our mission to ensure justice for the victims.”

“We are working tirelessly to apprehend those responsible and bring them to justice,” police said. “The Birmingham Police Department is dedicated to protecting our community and restoring a sense of safety and security.”