CHICAGO (CBS) — Chicago police have asked the Cook County State’s Attorney’s Office to review a shooting in which an officer shot an unarmed man Friday afternoon at the Grand station on the CTA Red Line for possible criminal charges, the state’s attorney’s office confirms.

The state’s attorney’s office is also working with the FBI on the investigation.

Two officers got into a struggle at the Grand station on the CTA Red Line after the officers tried to stop the man from moving between train cars. Video of the incident was posted on social media.

Deputy Police Supt. Barb West on Friday night said the officers were assigned to the mass transit unit and observed the man improperly moving between train cars, which is against city ordinance. They engaged with the suspect on the platform when the struggle ensued. The shooting is being investigated by the Civilian Office of Police Accountability and the Cook County State’s Attorney.

“Due to the criminal nature of this incident, we have asked the state’s attorney to respond,” West said.

The officers have been placed on administrative duties. Interim Supt. Charlie Beck  has been briefed and was decribed as “extremely concerned” about the incident. “We are conducting concurrent administrative and criminal investigations,” West said.

Video posted on social media shows two officers struggling to handcuff the suspect on the train platform at the bottom of the stairs.

They tell the man to stop resisting and both deploy their taser. The man breaks free, staggers to his feet and appears to wipe his face, apparently from pepper spray.  One of the officers then steps back and pulls her weapon and yells, “Sir, put your hands down!”  The second the officers yells, “Shoot him.” Although it is unclear whether he meant with more pepper spray or use of force. Earlier, an officer said “shoot him” and the other officer used pepper spray.

Then a shot is fired by one of the officers and the man runs up the escalator. Both officers pursue the man.  After the man reaches the top of the escalator, another shot is heard off camera.  One of tasers is also seen on the escalator stairs. Another video on social media shows the man lying at the top of the escalator unresponsive with two officers standing over him. It is unclear if those are the same officers who pursued the man up the steps.

As the struggle continues for at least three minutes, the man is heard saying, “I didn’t do nothing to you guys!”

Mayor Lightfoot tweeted that the video was “extremely disturbing.”

The Chicago Fire Department confirmed the man was taken to Northwestern Memorial Hospital in serious to critical condition. He remains in critical but stable condition after surgery.

“We were getting ready to board the train and all you heard was gunshots,” said Mykol Cooper. “Everybody took off running.”

Fire Department officials also said two officers were taken to Rush University Medical Center in good condition, although it was not immediately clear why the officers were hospitalized.

The CTA said Red Line trains were not stopping at Grand due to police activity.

The shooting comes on the same day Chicago Police Supt. Charlie Beck announced the department would be adding 50 officers to its mass transit unit, creating a team of four detectives dedicated to investigating crime on the CTA, and building out a new “strategic decision support center” at the Central District station, capable of monitoring all 32,000 surveillance cameras on the CTA in real time.