District Attorney Michael A. Ramos on Wednesday filed a request for the first gang injunction in county history, targeting the South Side Rialto gang, which has been active in that city for decades.

Wednesday morning, 120 law enforcement officers raided homes of 16 suspected South Side members, arresting 15 of them. Some were questioned and released, but others had outstanding warrants and remained in custody.

Officers also confiscated 22 firearms and gang paraphernalia.

The injunction, filed in Superior Court, prohibits the 60 or so active South Side members from congregating or sporting gang tattoos or gang attire in a roughly two-square-mile area of the city of Rialto.

Violators could be fined or spend up to a year in jail, officials said.

“These gang members have been involved in homicides, assaults with a deadly weapon, shootings and other violent crime,” Rialto police Lt. Joe Cirilo said.

The injunction, he added, “is not a save-all, but it's a tool to use so we can take gang members off the streets.”

Ramos said more gang injunctions will be filed, calling them part of a larger effort to reduce gang activity in the county.

Such injunctions have become common. Los Angeles has obtained a number of them, including one issued in April against a gang in the San Fernando Valley.

An injunction issued last year in Orange County reduced crime. Statistics showed gang-related calls to sheriff's deputies in the affected areas over a three-month period dropped 85 percent and 33 percent compared to the previous year.

But sometimes the gang members simply move and set up shop again.

San Diego County sheriff's Sgt. Gary Floyd said in May that about a dozen gang members had moved into a luxury apartment building near Cal State San Marcos and were selling drugs to students. The gang members were believed to be part of a southeast San Diego gang forced out of town by an injunction.