THE BRONX — An NYPD officer sprained her arm when a man she told to stop urinating on the street dragged her with his Cadillac in Port Morris, police said.

The 42-year-old officer was on the steps of the 40th Precinct stationhouse Monday about to begin her midnight tour when she saw a man urinating near the intersection of 138th Street and Alexander Avenue, an NYPD spokeswoman said.

When she went to question him, he offered to shake her hand before retreating into his 2009 Cadillac, police said.

He started the engine, but she leaned into the window and asked him to hand over his license and turn off the car's engine, police said.

Instead, he put the car into reverse and dragged her several feet, spraining her left shoulder, police said.

The driver, who is about 5-foot-8 and between 45 and 50, fled the scene and hadn't been arrested as of Tuesday morning, police said.

He drove the car over the Third Avenue Bridge into Manhattan where he ditched it at Fifth Avenue and 125th Street, police said.

The officer was treated and released from North Central Bronx Hospital, police said.