Two Harvard graduate students were mugged by different men who claimed to be carrying guns in separate incidents early yesterday morning.

Both suspects are still on the loose, and the Harvard University Police Department (HUPD) issued a community warning today after the incidents.

The first robbery occurred at 12:27 a.m. opposite 16 Holden Street in Cambridge, according to HUPD spokesperson Peggy A. McNamara.

A short, white man wearing a dark jacket and cap approached two graduate students from behind and demanded their wallets.

He did not show a weapon, but he pointed to his pocket and made threatening comments indicating he had a gun.

The suspect took both men's wallets and fled down Kirkland Street.

The suspect is described as approximately five feet tall, 20 years of age, with a round face, a distinctive nose and close-cropped hair.

The second incident occurred at 1:58 a.m. in the parkling lot behind Perkins Hall.

A stocky, blond man approached one graduate student, said he had a gun and demanded money.

He stole $20 from the victim and fled toward Oxford St.

The suspect is described as 5'9" and wearing a dark-blue hooded sweatshirt with a GAP logo and baggy blue pants.

McNamara said HUPD officials notified the Cambridge Police Department (CPD) and officers from both departments searched both areas but were unable to locate the suspects.

Anyone with information about the crimes is encouraged to call HUPD's criminal investigations unit at 617-495-1796 or CPD at 617-349-3300.

—Staff writer Alex B. Ginsberg can be reached at ginsberg@fas.harvard.edu.