NEW YORK - It was a tally so impressive that President Donald Trump touted it at his State of the Union address: Since May, agents cracking down on the violent gangs terrorizing the working-class suburbs of Long Island had swept up 428 gang suspects, including 220 members of the notorious MS-13.

But the sweep, Operation Matador, also has been shrouded in secrecy. Federal and state authorities have declined repeated requests from The Associated Press for even basic information made public in most law enforcement operations, such as the names of those arrested and the crimes they are accused of committing.

They won't divulge their ages, immigration statuses or current whereabouts. And while they say 44 of those arrested have been deported, they refuse to say what happened to the rest, including whether they are even still in custody. They say releasing more details could endanger the suspects and jeopardize ongoing investigations.

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The lack of transparency comes amid accusations by immigration rights groups that the government is using unsubstantiated rumors of gang affiliations to detain innocent people. Federal immigration judges have already ordered the release of some detainees arrested on suspicion of being MS-13 members when the government couldn't produce any evidence of gang activity.

READ: MS-13 gang violence: Mounting alarm as feds respond

Some parents and activists say some of those included in the tally are innocent teenagers who came to the U.S. as unaccompanied minors, spending weeks locked in maximum-security detention centers based on flimsy and false allegations of gang activity. Civil liberties lawyers say that in some cases their alleged "activity" was wearing a black T-shirt or making a hand gesture.

"They said we have a warrant for your arrest and we don't have to explain anything to you now. We will tell you when you come with us," one teenager, who asked not to be named because she is afraid of being deported, told the AP in Spanish. "Later, they told me I had been associated with gangs."

The teenager said she was not a member of MS-13. She said she knew of people in MS-13, as do most people at Brentwood High School, a large school 45 miles east of New York City. Maybe she's talked with some of them in the hallway.

Although she was released after two months in detention, she remains worried.

"I can't defend myself," she said. "I can't explain what happened because I don't even know who is accusing me."

Immigration attorney Dawn Guidone said she represented about seven teenagers detained on gang allegations and at least two were deported. One student said all he did was wear blue, the color of the gang. Officials said he was associating with "known gang members."

"But the gang member he was associating with sat next to him in math class," Guidone said. "If that's associating, then I don't know how to even deal with that."

The federal agency leading the crackdown, Homeland Security Investigations, said that of the 428 gang suspects mentioned in the Republican president's speech, 216 faced criminal charges, but it wouldn't say whether those charges had anything to do with gang activity or violence. It said the remaining 212 were detained for suspected immigration law violations but refused to disclose their names, citing privacy concerns.

Suffolk County District Attorney Tim Sini has refused to answer questions about MS-13 arrests for more than a year.

In neighboring Nassau County, prosecutors said they "took down the alleged kingpin of MS-13 for the entire Eastern region of the United States," but they refused to name the suspect, who's awaiting extradition from Maryland. A spokesman for prosecutors said the man's identity is being withheld because an indictment naming several co-defendants is sealed as it pertains to him.

MS-13, or La Mara Salvatrucha, recruits young teenagers from El Salvador and Honduras, though many gang members were born in the U.S. Long Island has a large population of unaccompanied minors from Central America, including many who were fleeing the violence in their home nations.

The gang has been blamed for at least 25 killings since January 2016 across a wide swath of Long Island. And many other people are missing.

In a July visit to Suffolk County, Trump promised his administration would "dismantle, decimate and eradicate" MS-13.

"They're going to jails, and then they're going back to their country, or they're going back to their country period," he said.

Last year, the American Civil Liberties Union filed a class action lawsuit in California claiming some teenagers arrested in the gang crackdown were being wrongly held at detention centers.

A federal judge overseeing the case ruled the plaintiffs deserve prompt hearings and released at least nine. The judge ordered the government to disclose how many were being held. The government has not done so.