Two men are at large after robbing a group of University employees at gunpoint outside Mather House last Thursday night, police said.

The men approached three staff members, whose names authorities would not release, in front of the Mather House gate at 9:55 p.m. as they sat in their car with the motor running.

Cambridge Police Department (CPD) Sergeant Lester J. Sullivan said one of the robbers barked "give me all your money" as he stuck a small black handgun through the window. The victims complied, handing over pagers, keys and wallets containing credit cards and $150 in cash.

The robbers then fled the scene, running down Cowperthwaite Street and then taking a right onto Banks Street before the victims lost sight of them.

Both CPD and Harvard University Police Department (HUPD) officers responded to the site of the robbery. Ten to 15 cruisers were present at the peak of police activity, according to Dr. Cheng-San "Louie" Chen, who saw the police response from his shop, Louie's Superette, which is located near the crime scene.

According to the authorities, the suspects are two black youths, 17 to 20 years old. The victims described the robber with the gun as a 5'8, dark-skinned male, with a muscular build, a round face and large teeth. He wore a dark-colored bandana, a dark plaid shirt, a black leather jacket and blue jeans.

The second suspect was described as a dark-skinned male, about six feet tall with a thin build. He wore a dark-colored waist length jacket and blue jeans.

The Mather tower is being used to house students working for several college-sponsored projects this summer, including Project Health, a community service program affiliated with Boston Medical Center.