A male graduate student was allegedly attacked while walking on Putnam Avenue at approximately 9:25 p.m. Wednesday, according to a community advisory e-mail issued yesterday morning by the Harvard University Police Department. The attack was allegedly part of an attempted armed robbery.

According to the advisory, the assailant approached the student from a driveway, struck him in the head, and tried to take his backpack, which contained his laptop computer.

Although the student was initially able to run away, the suspect caught up to him at the corner of Flagg Street and Putnam Avenue, according to the advisory. The assailant then revealed a handgun, after which the victim dropped his backpack and ran away.

The student was not injured in the incident, the advisory said.

The Cambridge Police Department is investigating the incident because it did not occur on Harvard University property.

HUPD sent a community advisory e-mail yesterday morning to all students, faculty, and staff at Harvard’s Cambridge Campus, and to some at the Longwood campus, according to HUPD spokesperson Steven G. Catalano.

The e-mail is the second of its kind to be sent out this week, before which no advisories had been sent out since September.

Students expressed concern about the recent crimes on campus.

“There’s certainly reason to be vigiliant and aware,” said Alexander E. McNaughton ’11.

The department sends advisories directly to Harvard College and the Graduate School of Arts and Sciences, as well as the deans of the schools, department public affairs officers, and the Director of News and Public Affairs for the University.

They also ask representatives to post the advisories in conspicuous locations on campus in addition to electronically forwarding them widely to students, faculty and staff.

Prior to yesterday’s, the last advisory was sent out this Tuesday, detailing an attempted robbery that had occurred in the Science Center plaza.

Since 2007, ten such community advisories have been issued by the police department.

CPD public information officials could not be reached Thursday evening.

—Staff writer Marianna N. Tishchenko can be reached mtishch@fas.harvard.edu.