Chicago Police Superintendent Eddie Johnson said two plainclothes officers working in a tactical unit in the 9th district were working in a tactical unit in a follow-up investigation to a separate incident when two vehicles pulled up alongside them and began firing indiscriminately at about 9:10 p.m. The officers returned fire.
Johnson clarified that the officers were not caught in crossfire, but were fired at, but that it is still the early stages of the investigation and the exact motive for the shooting is unclear.
One officer was hit in the back and the other officer was hit in the arm and hip, Johnson said. They were taken to Stroger Hospital in serious condition where they stabilized. Johnson said the officers are now doing "quite well, thank god."
An extensive manhunt is underway for the individuals responsible for the shooting. Johnson said police have recovered multiple weapons that may have been involved in the shooting, as well as a vehicle that may have been involved in the shooting. The investigation is ongoing.
Johnson said "a few" persons of interest are being questioned at this time.
"Make no mistake, we're gonna catch 'em. We are going to get these individuals responsible. Because, listen, if they are going to fire at police officers like that then they have no thought process in terms of firing at other citizens of this great city. So we are going to get 'em," Johnson said.
WATCH: CPD Supt. Eddie Johnson on police officers shot
Chicago Mayor Rahm Emanuel and the CPD command staff joined Johnson at Stroger Hospital to see the officers.
Police have set up a perimeter at 35th and Morgan as part of their manhunt. A police helicopter is also involved.
Witnesses said a flurry of gunfire erupted, as many as 30 shots, and some said it sounded like an assault rifle.
A witness who declined to give her name said she was waiting for a CTA bus on Ashland when she saw a wave of police cruisers speeding to the scene.
"They weren't messing around," she said. "I've seen shootings but I've never seen anything like that."
The shooting drew a massive police response as detectives investigated just past the entrance to the Old Union Stockyards.
The Sun-Times Media Wire contributed to this report