A 23-year-old Mexican man who was brought to the US illegally at the age of seven has been arrested and detained, despite having a valid work permit, the media reported.
Daniel Ramirez Medina was protected from deportation under one of former US President Barack Obama’s policies, BBC said.
He has a job, a young son and no criminal record.
Ramirez was taken into custody on Friday and is being held in Tacoma, Washington.
US Immigration and Customs Enforcement (ICE) agents had intended to arrest his father at home in Seattle, but also detained Ramirez.
In a statement, an ICE spokeswoman said the 23-year-old had told agents he was a gang member, and was taken into custody for being a “risk to public safety”.
Mark Rosenbaum, one of Mr Ramirez’s lawyers, said he “unequivocally denies being in a gang”.
He said Ramirez had been “repeatedly pressured” by customs agents to falsely admit to gang links while in custody.
Ramirez’s legal team say this could be the first time under the Trump administration that a person covered by the Deferred Action for Childhood Arrivals, or DACA, has been taken into immigration custody.
DACA was established in 2012 by then President Barack Obama to allow those brought to America while young to attend school and work without fear of deportation.
There are more than 740,000 people in the programme.
The arrest is being seen as significant given US President Donald Trump’s long-standing promise of an immigration clampdown.
In January, he issued an executive order expanding the remit of Homeland Security officials so they can target not only immigrants with serious criminal records, but also those with minor offences or no convictions to their names.
Hundreds of undocumented migrants have been arrested in recent days, in at least 11 states.
“The crackdown on illegal criminals is merely the keeping of my campaign promise,” the President wrote on Twitter. “Gang members, drug dealers & others are being removed!”
Trump said he would scrap DACA during his election campaign, but his policy on those it already covers is not yet clear.
In an interview with ABC News last month, Trump said they “are here illegally” but “shouldn’t be very worried”.