Los Angeles prosecutors on Monday filed California's first lawsuit seeking to seize homes, businesses and other assets from known members of the city's largest gang to cripple their criminal enterprises.

The lawsuit, filed against nine leaders of the 18th Street gang who are all serving prison time, is believed to be the first of its kind in the United States. It aims to reduce the wealth accumulated by gang leaders through illegal activities.

"The days of allowing vicious gang criminals to accumulate and spend their ill-gotten gains — sometimes even from behind bars — are over. It's time the gang leaders literally pay for their crimes," City Attorney Rocky Delgadillo said.

A state law passed earlier this year allows cities to sue for the financial damage gangs cause communities. Only gangs already targeted with restraining orders declaring their behavior a nuisance can be sued. Family members of gang members also can have items taken away if it's proven they are proceeds earned through criminal activity.

Damages gained from any lawsuits would be funneled back to the neighborhoods through programs and other measures.

Frank Mateljan, a spokesman for the city attorney's office, said he didn't know if any of the jailed gang members named in the action had retained attorneys.

Gangs typically profit from money laundering, drug sales and extortion of street vendors. In the area just north of downtown Los Angeles dominated by the 18th Street gang, people can be "taxed," as extortion is known on the street, as much as 30 percent, said Bruce Riordan, the city attorney's director of anti-gang operations.

Authorities said as many as 35,000 people statewide claim to be members of the 18th Street gang.

"Los Angeles is making good use of this new tool to hold gang members accountable for their actions, and I hope other California cities will follow," Gov. Arnold Schwarzenegger said in a statement.

Police said there has been a 33 percent decline in gang membership in the past seven years.