Allentown police are investigating an armed robbery at a city convenience store.

Police said a man walked into the Wawa at 911 Union Boulevard around 12:20 a.m. Thursday and said he had a gun--his hand was covering something as though he was holding a gun.

The clerk opened the register, the man grabbed an undetermined amount of money and fled, police said.

Half of the man's face was covered by a white cloth. He is described as a black man in his 20s, thin build, around 6 feet tall.

He has short black hair and was wearing eyeglasses, a light-colored polo shirt and blue jeans.

No one was hurt in the incident.