LOS ANGELES -- More than 1,000 Los Angeles police officers and federal agents arrested dozens of suspected gang members in a crackdown on the "Rolling 40s" gang early Thursday morning.

Authorities swarmed 47 locations in South Los Angeles with warrants for 75 individuals, according to Los Angeles police Deputy Chief Kirk Albanese. By early morning, some 46 people were in custody, he said.

The suspects, believed to be leaders of the violent street gang, were wanted primarily for drug and gun crimes.

Officers say they seized several weapons during the sweep, which began before dawn.

The arrests are the result of an 18-month investigation.

Officers were concentrated in the neighborhoods served by the LAPD's Southwest and 77th Street stations, including Exposition Park, Crenshaw, Jefferson Park, West Adams, Baldwin Village, University Park, Athens Park, Gramercy Park and Hyde Park.

Last week, federal authorities said nearly 300 people had been arrested in the Los Angeles area during a six-month national crackdown on criminal gangs.