Toronto police are investigating the second stabbing in less than a week at the Kennedy subway station following an altercation between two groups of people late Wednesday night.

A boy believed to be between 16 and 18 years old was stabbed twice in the back at about 11:30 p.m. while on the bus platform, police said.

The incident took place in front of a number of witnesses, who reported a fight between two groups of people after one group began picking on the other.

Following the attack, three men were seen running west from the station and across Kennedy Road. Bystanders also saw a white four-door car drive out of a nearby parking lot and head south on Kennedy.

The victim was taken to Sunnybrook Hospital, where he is expected to remain for a week while he recovers.

Police closed down the bus platform to investigate. Detectives interviewed the victim's friends and reportedly know the identity of the suspects.

Last Friday, police were called to the Kennedy subway station after a TTC worker found the lifeless body of Nick Brown on an empty train.

The 21-year-old was stabbed to death. Investigators have released several grainy surveillance camera images of a suspect but have not many any arrests.

TTC chairman Adam Giambrone says the commission is reviewing its security measures and will be installing more cameras and special constables in the coming months.

With a report from CTV's Roger Petersen