A man impersonating a police officer on Long Island abducted two teenage girls on Wednesday — groping one of them before she was able to flee, authorities said.

The creep stopped the girls — ages 14 and 16 — at about 3:35 p.m. as they were walking along Herbert Avenue in Lindenhurst en route to the library, police said.

He identified himself as an officer and said he would give them a ride to the library.

The teens got inside his car. The man then drove them to their destination, where he told the 16-year-old to get out because he needed to speak with the younger girl.

He then drove away with the 14-year-old girl to a nearby park and began touching her, cops said.

She managed to fight off the pervert and fled to a nearby home. The homeowner called the police.

The man remained on the loose as of early Thursday, police said.