A 35-year-old man was in good condition after he was attacked with a knife early Thursday morning after an altercation on a Red Line CTA train on the South Side, Chicago police said.

Shortly after 1:30 a.m., the man was approached by an unknown female suspect who pulled out a knife and began swinging at the victim. The victim was found on the platform in the first block of West 69th Street with lacerations to the face, ear and arm, police said.

Upon review of surveillance footage, CTA officials were able to determine an altercation between the female suspect and the victim.began on the train and carried out to the platform, according to Catherine Hosinski, a CTA spokeswoman.

He was taken to the University of Chicago Medical Center where he was reported in good condition.

No one was in custody for the knife attack, and detectives were investigating.