A violent altercation aboard SEPTA's Market Frankford Line led to a man being stabbed after an argument over smoking escalated, officials report. The incident took place around 12:25 p.m. near the Spring Garden Station in Philadelphia’s Northern Liberties area. As per NBC Philadelphia, the conflict began when a woman repeatedly asked the man to stop smoking on the train. He responded by punching her in the face, which prompted the woman to defend herself by stabbing the man in the arm and stomach.

The woman, having stabbed the man while claiming self-defense, is cooperating with police as they investigate the incident, according to The Philadelphia Inquirer. The man was subsequently transported to Thomas Jefferson University Hospital with injuries that were deemed non-life-threatening. SEPTA officials have stepped up enforcement against quality-of-life violations, such as smoking, which had only been enhanced since July.

Moreover, as detailed by PhillyVoice, the scene unfolded when the train operator called the police to respond to the stabbing at the station. No charges have been filed against the woman as of yet, and police are not releasing the names of the individuals involved while the investigation continues. There have been no citations reported in connection with the smoking violation specifically.