Portland police said young men held up a convenience store wearing Halloween masks in northeast Portland.
It happened at Cully Mini Mart just before 9 p.m. Tuesday.
Officers said the suspects looked to be about 16 or 17 years old.
They said one of the robbers was carrying a shotgun while the other was holding a knife and a duffle bag.
Police searched the area but were unable to track the suspects down.
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