THE BRONX - The NYPD is doubling the size of its gang unit in an effort to crack down on social media-driven "street crews" throughout the city.

Commissioner Ray Kelly announced the new initiative dubbed "Operation Street Crew," which will target loosely affiliated groups of teens. He says they often identify themselves by the blocks where they live and are responsible for much of the violence in public housing.

Part of the plan will increase the gang unit from 150 to 300 detectives. Officers will also utilize social media sites, which they say are often used to post threats and name targets.

Kelly says different divisions will be involved in the expansion, including youth officers from the Juvenile Justice Division. The youth officers will headquarter their investigations on Facebook and Twitter. They will also keep a log of slang terms to help better recognize threats between gang members.

Kelly says the young people targeted in the crackdown are unlike traditional street gangs involved in drug dealing. Instead, they're mostly concerned with protecting their turf.