United States Attorney General Jeff Sessions promised to crack down on the MS-13 gang Friday while in Central Islip.

His promise comes after what are believed to be the gang-related killings of several young people in Central Islip and Brentwood.

The parents of slain Brentwood teenagers Nisa Mickens and Kayla Cuevas said they had a positive experience during their one-on-one meeting with Sessions. Both girls were killed last September by members of MS-13.

Sessions also talked tough about the gang to a room full of Long Island law enforcement, and then took reporter questions. When asked how he thinks the situation with MS-13 got to its current point, Sessions said, "Even the mafia tends to come back after they've been hammered, and we will do so, and this time we will try to keep the pressure on."

Sessions was also asked if he could "reassure" undocumented immigrants who report crimes that they would not be deported. He did not, saying, "It cannot be that the attorney general grants immunity contrary to the law with people who violate the laws of the United States."

Afterward, both Nassau and Suffolk's police commissioners said their policy officers do not ask the immigration status of crime victims or witnesses.

Immigration advocates say Sessions' comments about illegal immigration could hurt local enforcement in their war against gangs, because police sometimes rely on undocumented immigrants to provide information about crimes.

The families of other victims of MS-13 showed up at the courthouse Friday, hoping to meet with Sessions, but were not allowed to since all those in attendance were invited ahead of time.