BELLPORT, N.Y. — Some immigrant high school students are being unfairly swept up in a growing hysteria over the brutal MS-13 street gang, civil rights lawyers said.

At least nine students from Long Island’s Suffolk County, east of New York City, have been sent to U.S. immigration detention facilities after being falsely labeled as gang members, the New York Civil Liberties Union said.

None of the teens had ever faced criminal charges related to gangs, and in some cases their alleged gang activity was wearing a black T-shirt or making a hand gesture, the NYCLU said.

“No child deserves to have his life upended or be ripped away from family based on flimsy allegations,” NYCLU Executive Director Donna Lieberman said. “Children who in many cases came to America to flee gang violence are being disappeared to face deportation without adequate protections or investigation.”

The organization wrote Thursday to the U.S. Office of Refugee Resettlement, which has jurisdiction over minors who enter the U.S. illegally unaccompanied by their parents, saying it believed the teens’ detentions violated a federal court order and U.S. law.

MS-13 violence on Long Island began to get attention last summer, when two students at Brentwood High School — best friends Nisa Mickens, 15, and Kayla Cuevas, 16 — were beaten and hacked to death in a suspected gang attack. They were among 17 people believed to have been killed by the gang on eastern Long Island since the start of 2016. Most of the people arrested in those killings were in the U.S. illegally, law enforcement officials have said.

In a visit to Brentwood on Friday, President Donald Trump promised to use tough enforcement of immigration law to get gang members thrown out of the country.

“They butchered those little girls,” the Republican president said. “They kidnap. They extort. They rape, and they rob. … They shouldn’t be here.”

Immigration and civil rights lawyers, though, said a crackdown in some Suffolk County schools has gone too far.

The NYCLU said one student was suspended for wearing a Chicago Bulls shirt, a possible gang symbol, to school and another for posting an El Salvadoran flag on a Facebook page.

Attorney Peter Brill, who represents three students suspended from Bellport High School, said one was later detained by immigration officials. All three were from Central America and initially entered the U.S. illegally.

“They all vehemently deny being involved in gangs,” Brill said. “They all fled their countries to get away from gang violence. This doesn’t make sense.”

Two students at Bellport High were among four people massacred in a park in Central Islip in April in a suspected MS-13 gang attack.

Joseph Giani, superintendent of schools in the district that oversees Bellport High, stood by the students’ suspensions and denied disclosing student information to police.

Suffolk County police Commissioner Timothy Sini told The New York Times last month there were times when officers couldn’t make criminal arrests so officers work with federal immigration officials to target known gang members “for violation of civil immigration laws, which is another way to remove dangerous individuals from our streets.”

Children who enter the U.S. illegally, unaccompanied by their parents, are treated differently under U.S. law. They aren’t immediately deported if caught at the border, like adults, and can be placed with relatives in the U.S. while they undergo a lengthy vetting process.

The NYCLU said a consent decree signed in 1997 and a federal law enacted in 2002 require juvenile detainees be placed in the least restrictive setting unless it’s determined they pose a threat to themselves or others. Juveniles also must have the ability to contest the detainment.

“This is causing us concern, where labeling someone as gang affiliated is not enough to make a criminal arrest,” attorney Philip Desgranges said. “But it’s causing kids to spiral into this system where they’re whisked away.