Toronto police are searching for a suspect who allegedly struck a teen in the face with an object on a subway train downtown and then fled.

The suspect and a 17-year-old youth were on a southbound TTC train pulling away from Museum Station at around 3 p.m. on Jan. 31.

According to police, the suspect struck the victim in the face with an object before fleeing at St. Andrew Station, at King Street and University Avenue.

The two did not know each other, police said.

Investigators did not say what object the suspect used to strike the victim, but said they are treating the incident as an assault with a weapon.

The suspect is described as 20 to 25 years old, with short dark hair and a short beard. He was wearing a green puffy winter coat, with a black and green hooded sweater, and beige pants with black laced shoes.

Investigators have released an image of the suspect and are asking anyone with information to contact police.