A man allegedly grabbed a woman's buttocks twice before he ran away from an Astoria subway station last week.

Cops are looking for the man, who officials said accosted the woman on a Queens-bound N train the evening of Sept. 18.

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Authorities said the unidentified woman was standing in the train car when the man behind her suddenly ran his hand across her rear end.

The woman called out the man's wandering hand and confronted him, she told police, who said the man escalated the station by grabbing her buttocks before he ran away from the Broadway and 31st Street station.

Before he ran away, however, the woman used her phone to take a picture of the suspect.

Investigators described the man as white and between 30 to 35 with blue eyes and black-framed glasses. He stood about 6 feet tall and with a stockily build.

He was last seen wearing a black knit hat, a green shirt, blue jeans and carrying a backpack.

NYPD asks that anyone with information about the suspect call the NYPD's Crime Stoppers Hotline at 800-577-TIPS or text their tips to 274637 (CRIMES) then enter TIP577.