A 31-year-old man was robbed at gunpoint early Tuesday outside a gas station in Westbury, police said.

While walking to the Citgo at 495 Union Ave., the victim saw two men standing in front of 200 School St. After the victim discovered the gas station was closed, one of the men approached him and they spoke briefly, police said.

The robber then walked behind a van in the parking lot where he donned a mask, and reappeared, brandishing a dark handgun.

The robber demanded the victim’s money, then fled north on School Street.

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No injuries were reported; the robber was described as being in his mid-20s to early 30s. He wore a blue, long-sleeved shirt, and dark pants.

The police, who are investigating, ask anyone with information about the robbery to call 800-244-TIPS. All callers will remain anonymous.