A Long Island man was gunned down and killed in Brooklyn early Friday, police said.

Cops responding to a report of shots fired around 3:15 a.m. discovered the 29-year-old victim with a fatal gunshot wound to the head, lying on the sidewalk near Williams and Atlantic avenues in Cypress Hills, police said.

The victim, a Nassau County resident, could not be saved. Police are not releasing his name pending family notification.

His attacker is still on the loose.