CARLSBAD, Calif. -- Police are looking for a man who claimed to be armed when he threatened a clerk's life and robbed a Carlsbad gas station on Christmas Day.

The suspect entered the Shell gas station on 665 Palomar Airport Road just minutes before 6 p.m. Friday and told the clerk that he wanted to buy a pack of cigarettes, said Carlsbad police Lt. Paul Mendes.

The suspect produced a $5 bill and when the clerk opened the cash register, the robber told him that he would get shot unless he handed over all the money, Mendes said.

The clerk handed over about $100, which the suspect took along with a pack of cigarettes. The robber then fled in an unknown direction, according to the lieutenant.

The employee told police that the suspect was at the gas station earlier in the day. The clerk added that he never saw a weapon on the suspect, Mendes said.

The suspect was described as a white male in his late 30s with a medium to heavy build. He was last seen wearing a blue shirt, jeans, gray knit hat and sunglasses, Mendes said.