A feeling of dread is rippling through one particular group in the United States, as hundreds of thousands of young people fear they might have to hide in society's shadows during a Donald Trump presidency.

It's a sudden shock.

More than 800,000 young people have just left those shadows at the invitation of President Barack Obama — as children, they were brought illegally to the U.S. by their parents, and Obama allowed them to apply for work permits.

Now the U.S. government has their personal information.

As the election results rolled in, fear set in. The president-elect is threatening to deport them. Trump's platform promises to terminate the Obama executive order that let them work; triple the number of immigration officers; and accelerate deportations.

A headline in the conservative Washington Examiner referred Friday to the group as a sitting target: ''(A) deportation hit list.''

That includes one young woman protesting outside Trump's hotel in Washington this week. She declined to be interviewed out of fear of being exposed. Immigration lawyers are urging people to avoid sharing their information.

The National Immigration Law Center has posted instructions on its website under the all-caps headline: ''IMPORTANT NOTICE — PLEASE READ.'' It instructs people to stop applying for these permits.

It also advises young people to remain silent if arrested, and request an attorney. If they're guarding young children, they should make emergency plans for someone to care for them. They are also advised to memorize phone numbers for a lawyer or family members.

Another protester outside the hotel was American, free to speak on behalf of worried friends.

''It's a dangerous place to be — to be undocumented and be out,'' said Flannery Wasson, holding up a sign outside the hotel entrance.

''So I've been trying to help as much as possible.''

Wasson said she has a friend with a master's degree, another who's finished college, and a third who's lived in the U.S. for as far back as his memory goes — all of them now living under a new cloud of uncertainty.

She said she recalled people crying the day Obama's executive order gave them new stability.

The 2012 order titled Deferred Action for Childhood Arrivals, best-known under its acronym, ''DACA,'' applies to people who were under 16 when they arrived in the U.S., before 2007; are studying or have graduated high school; have served in the military; and have no criminal felonies or repeat misdemeanours on their record.

They can get two-year, renewable work permits — and at least 819,512 have, according to U.S. Citizenship and Immigration Services, with about 50,000 rejected. These youngsters are just a fraction of the estimated 11 million undocumented people living in the U.S.

More than two-thirds of applicants are from Mexico. Most of the rest are from Latin America. Thousands are also from South Korea, India, and the Philippines.

Many people doubt Trump will carry out deportations that will rip apart families, communities and workplaces — especially not for this group, comprising people who came to the U.S. as children; don't all speak Spanish; and in many cases only know this country.

Yet that threat remains on his website.

''(He will) immediately terminate President Obama's... illegal executive amnesties. All immigration laws will be enforced,'' says the Trump platform.

''Anyone who enters the U.S. illegally is subject to deportation. That is what it means to have laws and to have a country.''

To many Americans, it's a development worth celebrating. One group urging reduced immigration published a blog post saying it was foolish of these people to apply in the first place.

''I was surprised anyone would be stupid enough to sign up,'' said the post from John Miano, who has studied and written about the negative relationship between low-skilled immigration and workers' wages.

''Yet apparently hundreds of thousands of people did... Now that the election is over and it is clear that (the executive orders) will soon be kaput, people are beginning to realize that (they) have created a list of prime candidates for deportation with names, addresses, and an admission of illegal alien status.''

Others are preparing.

Wasson is gathering information and sharing it with friends.

''Experts are saying right now, keep your documents close to you. Make sure you have a safety plan. Make sure you've talked to someone,'' she said.

''It's that dire of a situation.''

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