The FBI says the man approached the teller with a note that both demanded money, and said he had a gun.
Once he had some cash, authorities say the man ran down Frankford Avenue and then east on Orthodox Street.
The suspect is described as either a hispanic man, or a black man with a light complexion. He's said to be in his mid 30's, approximately 5'8" to 5'9", with a husky build. He had dark eyes, very short black hair and a goatee with scruffy facial hair. He was wearing a bright blue oversized t-shirt, black shorts and sunglasses on the top of his head.
Anyone with information regarding this robbery should contact the FBI at (215) 418-4000.