They grew up in America and are working or going to school here. Some are building businesses or raising families of their own. Many have no memory of the country where they were born.

Now, almost 800,000 young immigrants who were brought to the U.S. illegally as children or overstayed their visas could see their lives upended after the Trump administration announced today it is ending the Obama-era program that protected them from deportation.

“We are Americans in heart, mind and soul. We just don’t have the correct documentation that states we’re American,” said Jose Rivas, 27, who is studying for a master’s in counseling at the University of Wyoming.

Rivas’ grandmother brought him to this country from Mexico when he was 6. He wants to become a school counselor in America but lamented: “Everything is up in the air at this point.”

The news that the government is phasing out the Deferred Action for Childhood Arrivals program, known as DACA, over the next six months was met with shock, anger and a sense of betrayal by its beneficiaries, often called “Dreamers.”

Demonstrations broke out in New York City, where police handcuffed and removed over a dozen immigration activists who briefly blocked Trump Tower, and in other cities, including Salt Lake City, Denver, Los Angeles and Portland, Oregon.

Attorney General Jeff Sessions said DACA, started by President Barack Obama in 2012, was an unconstitutional exercise of executive power. The Trump administration and other DACA opponents argue that it is up to Congress to decide how to deal with such immigrants.

Attorneys general for several states threatened to sue to protect the DACA beneficiaries. “We stand ready to take all appropriate legal action to protect Oregon’s Dreamers,” Oregon Attorney General Ellen Rosenblum tweeted.

Ricardo Ortiz, who was brought to the U.S. from Monterrey, Mexico, at age 3, has been volunteering at the downtown Houston convention center that sheltered thousands of Hurricane Harvey victims.

Ortiz, a 21-year-old student at the University of Houston, said he doesn’t know what he will do if DACA is ended or he is forced to leave the country.

“It’s crazy that people really think that we don’t belong here when we’ve been here all of our lives,” he said.

Even small children would face deportation, among them students at Nellie Muir Elementary School in the predominantly Latino town of Woodburn, Oregon.

Vice Principal Oscar Belanger greeted them in English and Spanish on their first day of class, and told a reporter that administrators and teachers want Washington to stand by the Dreamers.

Belanger said the school would refuse to turn over students’ information to immigration agents, noting that Oregon law expressly prohibits that.

Utah Attorney General Sean Reyes, a Republican and an early Trump supporter, said the president has every right to end DACA. But he added that it would be unconscionable to deport Dreamers.

“These children grew up believing they are American and so many of them have lived lives of which America can be proud,” Reyes said in a statement.

Arkansas Attorney General Leslie Rutledge commended Trump’s decision.

“While we are a compassionate country, the United States is a country of laws and President Trump recognized that President Obama’s DACA program went far beyond the executive branch’s legal authority,” Rutledge said. “Congress has always been the proper place for this debate.”

In Miami, Paola Martinez, 23, who is from Bogota, Colombia, sobbed as she attended a rally of about 100 immigrants, and said she will feel helpless without DACA. She recently graduated with a civil engineering degree from Florida International University.

“Instead of going a step forward, we are going a step backwards. We are hiding in the shadows again after my work (permit) expires. It’s just sadness,” she said. “You just feel like you are empty. There is no support anymore.”

Martinez said she is not able to renew her permit because it expires in 2019, so she is hoping her employer or another company sponsors her so she can stay and help support her parents, who depend on her for rides and household expenses. In Florida, immigrants who are illegally in the country cannot get driver’s licenses.

Karen Marin, a 26-year-old from New York whose parents brought her to the U.S. before she was a year old, was in physics class at Bronx Community College when Sessions made the announcement.

“I honestly I can’t even process it right now. I’m still trying to get myself together,” Marin said. “I just hope that they do change their mind and they realize what they’re doing is wrong.”

Carla Chavarria, 24, is a Phoenix entrepreneur who owns a digital marketing firm and a fitness apparel line. She came to the U.S. from Mexico when she was 7.

Her permit expires in November and she is waiting for her renewal to be processed. She is set to close on the purchase of a home later this month.

“It’s hard being a business owner as it is, especially with being young and being a woman and someone who’s an immigrant. It’s already hard as it is. Now having DACA being taken away,” she said.

“I’m sort of like in limbo right now.”

AP reporters Adriana Gomez Licon in Miami; Nomaan Merchant in Houston; Michelle Price in Salt Lake City; and Astrid Galvan in Phoenix contributed to this report.