A woman was raped in a busy area of Central Square last Monday, prompting the Harvard University Police Department (HUPD) to issue its first community-wide advisory of the school year.

According to the Cambridge Police Department (CPD), the victim was standing at the intersection of Mass. Ave. and Pearl Street around 3:45 p.m. when she was grabbed from behind by a stranger and taken into the hallway of an office building. She was then sexually assaulted.

The attacker did not use a weapon, police said.

HUPD drafted its advisory, issued as students left for Thanksgiving break on Wednesday, because the victim reported seeing her assailant in Harvard Square hours before her assault.

Police are searching for the suspect, who is described as a 21-year old black male, standing five-feet-five inches tall, weighing 160 pounds with a thin build.

At the time of the attack, he was wearing a gray sweatshirt with a white logo on front and white baggy pants, which the victim thinks might have been jeans.

He wore a nylon-type scarf on his head, covered by a white headband.

Because of the holiday weekend, neither the HUPD spokesperson, Peggy A. McNamara, nor the CPD spokesperson, Frank D. Pasquarello, could be reached for comment.

The Central Square rape comes at a time of heightened tensions around the state. A string of sexual assaults and attempted assaults at the University of Massachusetts-Amherst and nearby colleges in the western half of the state has raised fears among many college students.

"[Students] should always be conscious of their safety, especially in areas they don't know as well, like Central Square," HUPD Sergeant Robert J. Kotowski said. "They should use all the methods of safe transportation available."

One of the most effective precautions students can take to improve personal security is to not wear headphones while they are out alone, Kotowski suggested.

Wearing headphones can distract a potential victim from his or her surroundings.

Last Monday's crime was an anomaly in Cambridge, which reported a 41 percent drop in rapes over the first three quarters of 1999. That drop continues a near constant 10-year downward trend in so-called "stranger rapes." Acquaintance rapes, where the victim knows the attacker, are more common.

The CPD asks anyone with information about the crime to contact Sergeants McSweeney or Sullivan. They can be reached at 349-3370 or 349-3301.