In the past three days, the Harvard University and Cambridge police departments have reported two violent unarmed robberies in the area around the Harvard campus.

On Tuesday afternoon, all Harvard students received a community advisory email regarding the two recent robberies.

The community advisory reported that two victims, both females in their early twenties, were approached and robbed at night. Both victims described their assailant as “a light skinned black or white male in his 30’s.”

The first victim was assaulted on Sunday night between 1:30 and 2 a.m. near the corner of Kirkland Street and Trowbridge Street, about five blocks northeast of Memorial Hall. The attacker threw the woman to the ground, knocked her unconscious, and then stole her iPhone and purse, according to the email.

The second victim was physically assaulted the next night at approximately 11:15 p.m. on the corner of Ellery Street and Harvard Street, about two blocks east of Pennypacker.

The Cambridge Police Department has neither confirmed nor discounted the possibility that the robberies were conducted by the same individual, according to Daniel M. Riviello, a police department spokesperson.

Detectives are working on finding the perpetrator of both robberies, and the CPD will conduct extra patrols in the area where the crimes were committed, Riviello wrote in an email.

Both of the victims were wearing headphones when attacked, and the advisory email warned against this in a list of precautions which also included staring at the ground and walking alone.

“We cannot stress enough that residents and students take care to follow the safety tips in the alert,” Riviello said. “Specifically to always be aware of their surroundings, walk in a group whenever possible, and avoid wearing headphones and listening to music so they are not distracted.”

This community advisory was the Harvard University Police Department’s first message to the student body this semester. The police sent mass emails in response to crimes on or near Harvard’s campus five times last semester.

In the 2010-11 academic year, HUPD released six community advisories in the fall semester and two in the spring.

—Staff writer Amy Q. Friedman can be reached at aqfriedman@college.harvard.edu.