An NYPD cop cut open his head during a struggle with a shoplifting suspect in Lower Manhattan Thursday afternoon, police said.

The accident happened on the sidewalk outside 300 Mercer Street around 3:10 p.m., according to police.

After a preliminary investigation, police said a shoplifter stole a pair of sunglasses from a nearby business and a worker there flagged down police outside.

The unidentified lieutenant chased down the thief, but when he tried to arrest the shoplifter fell, hitting his head on a wall, police said.

The lieutenant needed 60 stitches, police said.

A video shows a pool of blood on the side with at least a dozen cops around clearing the scene.

The officer was taken to Bellevue and is conscious and alert, authorities said.

Other officers who were part of the pursuit nabbed the suspect, who is in custody with charges pending, police said.