Sheriff's detectives are looking for two men who attempted an armed robbery Monday morning at a Houston service station in Fort Bend County.

The two entered a Valero gas station and convenience store, at 14195 Bissonnet Road, at about 7:30 a.m., according to a statement from the Fort Bend Sheriff's Office.

"One suspect, armed with a black semi-automatic pistol approached the store clerk who was located behind the counter, pointed the handgun at the clerk and demanded she open the safe, while the other suspect stood watch at the front door," the sheriff's office said.

But the clerk was unable to open the safe, and the two would-be robbers ran off empty-handed.

The suspect who pointed the pistol at the clerk was described as a black man 20 to 22 years old, 5 feet, 7 inches to 5 feet 10 inches tall, weighiug 160 to 170 pounds. The sheriff's office said he was wearing a light-colored hooded jacket, black pants and red shoes.

The other suspect was also a black man of the same approximate age, height and weight, the sheriff's office said. He was wearing a dark hooded jacket, light gray pants and a light-colored backpack.

Anyone with information about the robbery attempt or the suspects is asked to contact Fort Bend County Crime Stoppers at 281-341-8477.