Two teenagers were shot — one fatally — in a gang-related incident on a busy Downtown Brooklyn street Monday night, police sources said.

The shooting happened in front of an Applebee’s on Flatbush Avenue near Dekalb Avenue at around 6:10 p.m. over an apparent turf war between an East New York crew and a Fort Greene crew, sources said.

Armani Hankins, 17, took a fatal bullet to the head, cops said. Emergency responders rushed him to Brooklyn Hospital, but he could not be saved.

The other victim, an 18-year-old, suffered a gunshot wound to the ankle and was taken to Methodist Hospital in stable condition.

Before the shooting, a large group of men got into an argument, police said. At least two members of the Fort Greene crew opened fire on the East New York group, sources said.

Joanna Rodriguez, 18, the sister of the slain teen, said that her brother has been a part of the “425” street gang “for years.”