A 6-month-old boy and a 13-year-old girl were in critical condition Wednesday night after a shooting in the South Loop that wounded four people.

At 9:07 p.m., a male wearing a ski mask jumped out of a blue van or sports-utility vehicle and began firing at a car driving west through the intersection of West Cermak Road and South State Street, according to Chicago police.

The shooting stemmed from an argument between the people in the two vehicles that began about a mile and a half south of that intersection, Chicago Police Deputy Chief Kevin Ryan said in a late-night press conference.

The blue vehicle chased the car until crashing at the scene near the Cermak-McCormick Place Green Line station, Ryan said. Then a masked gunman exited the vehicle and unleashed a torrent of bullets that struck four of the car’s five passengers.

Among them were a 6-month-old boy, hit twice in the abdomen, and a 13-year-old girl who had a gunshot wound in her shoulder, police said. The two children were taken to Lurie Children’s Hospital, where their conditions were reported as critical but stable.

Police investigate a shooting that left an infant and teen wounded Wednesday, September 19, 2018 in the 100 block of West Cermak Rd. in Chicago. | Justin Jackson/ Sun-Times

A 37-year-old woman was shot in the knee and taken to Northwestern Memorial Hospital in serious but stable condition, police said. A 27-year-old man inside the car suffered a graze wound to the arm and refused treatment at the scene. The fifth passenger, a 15-year-old girl, was not shot.

Officials initially had said the younger shooting victim was a 16-month-old girl and that the wounded woman was 30 years old.

No one was in custody late Wednesday. The shooter was last seen getting back inside the van or SUV and possibly driving south on State Street.

Police investigate a shooting that left an infant and teen wounded Wednesday, September 19, 2018 in the 100 block of West Cermak Rd. in Chicago. | Justin Jackson/ Sun-Times

The shooting is not believed to be a road-rage incident, Ryan said. He also noted the area is “heavily covered” by video surveillance.

Area Central detectives were investigating.