Four cops were injured in a two-car crash Thursday night in Queens.

Three officers were traveling in an unmarked police car on Rockaway Boulevard near 101st Street in Ozone Park at about 11 p.m. when they collided with a car that coincidentally was being driven by an off-duty cop.

The three officers in the unmarked police cruiser were trapped in the wreck.

FDNY rescuers worked for nearly a half-hour to remove them, according to officials.

All four officers were taken to Jamaica Hospital with neck and back injuries, authorities said.

The cause of the crash was ­under investigation, according to police.