In other cities, gangs like the Bloods, the Crips and the MS-13 menace their communities with the efficiency of a business organization, with rookie "training," initiation rituals and a leader-soldier structure.

But Philadelphia's typical gang member is a school-skipper just getting his first mustache whose "gang" is his adolescent neighbors and whose crimes spring from turf battles with teenage toughs who live just a few streets over, FBI and city police officials said yesterday at a news conference about their joint gang-busting strategies.

That profile stymies authorities as they try to curb the climbing violent-crime rate in Philadelphia.

"Better than half" of the city's 1,800 shootings and 406 homicides last year were committed by such young neighborhood thugs, said Chief Inspector Joseph Fox, head of the police department's detectives. Last week's shooting outside Sayre High School, in which a 17-year-old student was injured by gunfire in an ongoing feud between teens from 56th Street and others from 60th Street, is a good, recent example, Fox said.

"Philadelphia is just saturated right now with these neighborhood groups whose affiliations are very fluid," Fox said.

Their youth and lack of organization make them "very susceptible to being recruited by more violent and more structured gangs," he added. "We don't want to see this [neighborhood thuggery] mushroom into something more organized."

Besides teenage toughs, the city's crime-fighters say law-breakers in the Latino community have also given them growing headaches.

The FBI is forming a new task force to ferret out and squash violent Latin gangs in Philadelphia, said Ron Hosko, the assistant special agent in charge of the FBI's Philadelphia office.

"We know that the bulk of the illegal drugs that end up in Philadelphia comes from Mexico, Central America and South America," Hosko said. "[Latinos] are integral to the drug-trafficking organization, the drugs that get into the hands of people who spread violence in the city."

Three other FBI-led task forces - in which agents partner with city police and other authorities - focus on organized crime, black gangs and violent crime/fugitives, Hosko said. *