New York police forces stormed two Harlem housing projects and arrested dozens of people in a massive security operation that saw more than 100 suspected gang members charged.

In the early morning, Some 500 NYPD officers wearing bulletproof vests descended upon neighbouring Manhattanville and Grant housing projects in Manhattan, which prosecutors said had been turned into a "war zone" by criminals.

Police said 40 people were rounded up. The arrests came as part of what has been described as the largest gang case in New York City's history.

Prosecutors indicted 103 alleged members from three gangs -- the allied Make It Happen Boys and Money Avenue, and their rivals, 3 Staccs -- for a string of violent crimes.

Aged between 15 and 30, the suspects had been allegedly involved in a violent four-year turf war on the streets of Harlem.

"For four years, these gangs have waged a campaign of violence simply for the sake of violence," Manhattan district attorney Cyrus Vance said.

The gangs are accused of two homicides, 19 non-fatal shootings and dozens of other shooting incidents.

One of the gangs' alleged victims was Tayshana Murphy, an 18-year-old high-school basketball star who was chased down by members of the Make It Happen Boys and shot dead in a hallway near her apartment in the Grant Houses.

The feud was not drug related but was over the partition of territory in the area, the city's police commissioner William Bratton said.

"They're not organised crime. They're not disorganised crime. It's all about violence."

Charges filed against the 103 include attempted murder, gang assault, criminal possession of a weapon and conspiracy.

Police said they are actively seeking 23 gang members while the remaining suspects had been already arrested prior to the sweep.