(Photo/U.S. Immigration and Customs Enforcement)

(CNSNews.com) - Ninety-nine confirmed MS-13 gang members arrested over the last eleven months as the result of a joint operation conducted by the federal Department of Homeland Security and local New York law enforcement agencies came across the border into the United States as “unaccompanied minors,” according to U.S. Immigration and Customs Enforcement.

Sixty-four of these 99 MS-13 gang members had been granted “Special Immigrant Juvenile Status” (SIJ) by the U.S. government after they crossed into the country, says ICE.

SIJ, ICE explains, is a classification that “provides certain children who have been subject to state juvenile court proceedings related to abuse, neglect, abandonment, or a similar basis under state law the ability to seek lawful permanent residence in the United States.”

“Ninety-nine individuals arrested during this operation crossed the border as unaccompanied minors, all of which were confirmed as MS-13 gang members,” ICE said in a statement.

“64 individuals arrested during this operation obtained Special Immigrant Juvenile Status (SIJ) after entering the country, all of which were confirmed as MS-13 gang members,” said the statement. “Of the 99 UACs, 64 had SIJ status.”

The arrests were made as part of “Operation Matador,” which ICE describes as a “unified effort to combat the proliferation of MS-13 and other transnational criminal gang activity in Long Island, the New York City metropolitan area and the Hudson Valley.”

Local law enforcement agencies--including the Suffolk County Police Department, the Nassau County Police Department, the Hempstead Police Department, the Rockland County Sheriff, the Piermont Police Department, the Ulster County Sheriff, and the Sullivan County Sheriff—have been working with DHS on the operation which began last May. On the federal side, ICE, U.S. Customs and Border Protection and U.S. Citizenship and Immigration Services have all been involved, according to a statement put out by ICE.

So far, the overall operation has resulted in 475 arrests.

“A total of 475 individuals were arrested during this ongoing enforcement effort, most of which were confirmed as gang members and affiliates,” said the ICE statement. “The most prominent gangs and arrests during this operation were MS-13 with 274 arrests and the 18th Street gang with 15 arrests.”

“Of the gang members arrested during this ongoing enforcement action,” said ICE, “80 had additional criminal histories, including prior convictions for assault and weapons charges. Five are facing serious criminal charges.”

Two of the MS-13 gang members arrested in the operation admitted to killings in their home countries. One arrestee, according to ICE, was an “MS-13 member from El Salvador who admitted to killing rival gang members at the age of 12 in his home country and assimilated to the gang on Long Island.” This individual, ICE said, was “arrested and deported.”

Another, according to ICE, was an “MS-13 member arrested in Brentwood [who] admitted to killing three gang members in El Salvador at the age of 13.”

The "vast majority" of the 99 MS-13 gang members who have been arrested in the operation and turned out to have crossed the border as unaccompanied minors were arrested by ICE's Homeland Security Investigations (HSI) department, says ICE.