A Harvard graduate student was beaten and robbed Wednesday in Cambridge Common after he spotted a man urinating on a tree, according to The Cambridge Chronicle.

The Harvard University Police Department issued an advisory to the University community two days after the incident urging affiliates to stay vigilant.

The Chronicle reported that the student was passing through the Common after coming from his gym when he saw a teenage male urinating in the park. He said he was then punched in the head by another assailant and, according to the community advisory, struck several more times by three additional males.

The group then proceeded to beat him to the ground and steal his gym bag, which contained his cell phone, iPod, and credit card, as well as various clothing items. The assailants fled towards Mass Ave.

The victim, who refused medical attention, had a swollen lip and two bumps on his forehead, the advisory said.

The Chronicle reported that the suspects were described as two white and two black 17-year-old males, which, according to the advisory, did not constitute a “detailed description.”

The incident was originally reported to HUPD by the Cambridge Police Department, who are running the investigation since the incident did not take place on University property.

—Staff writer Jamison A. Hill can be reached at jahill@fas.harvard.edu.