A 20-year-old man was shot in the head outside a Manhattan deli, leaving him clinging to life, police said Monday.

Shots rang out on Columbus Ave. near W. 105th St. on the Upper West Side about 11:40 p.m. Sunday, cops said.

Medics rushed the victim, struck in the head, to Mount Sinai St. Luke’s, where he is in critical condition.

The shooter ran off and is being sought.

The victim has prior arrests on charges including robbery, strangulation and drug possession, sources said. His name was not released.

It wasn’t clear what sparked the shooting.