A robber with a gun ran off with a taxi driver’s cellphone and money Thursday night in Riverhead, police said.

A male held up the driver just before 7 p.m. at Old Farm Road and Arrowhead Avenue, police said.

Officers searched the area for the suspect, who had a thin build and was neatly dressed in dark clothing, authorities said.

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Police did not release other details.

Investigators said anyone with information can call them at 631-727-4500.