Attorney General says administration will 'begin an orderly, lawful wind down' of 2012 Obama program.

President Donald Trump has decided to end his predecessor's program to shield from deportation children brought to this country illegally, the nation's top law enforcement official said Tuesday.

Attorney General Jeff Sessions defended the decision by claiming the move is in line with the Constitution's division of powers between the executive branch of government and Congress. He said the administration would "begin an orderly, lawful wind down" of the Deferred Action for Children Arrivals (DACA) program.

"The executive branch, through DACA, deliberately sought to achieve what the legislative branch specifically refused to authorize on multiple occasions," he said at the Justice Department. "Such an open-ended circumvention of immigration laws was an unconstitutional exercise of authority by the executive branch."

The attorney general did not take questions from reporters after delivering his statement. 

Trump earlier Tuesday called on Congress to "get ready to do your job" in a tweet referencing DACA. 

"Make no mistake, we are going to put the interest of AMERICAN CITIZENS FIRST!" a post he retweeted said. "The forgotten men & women will no longer be forgotten."

There will now be a six-month period in which Congress can pass a DACA replacement before the administration stops issuing new permits. 

The 2012 stopgap program allowed those who came to the U.S. illegally under the age of 16 to attain legal status for a renewable two-year term. Former President Barack Obama implemented the policy after Congress failed to pass immigration reform. 

An estimated 800,000 recipients benefit from the program, and are allowed to work legally in the U.S.

Some Republican state officials warned they would challenge the DACA program in court if the Trump administration did not rescind the program by Tuesday.

But some lawmakers also warned Trump against doing so.

Republican House Speaker Paul Ryan said Friday that Trump should refrain from rescinding the program, saying instead Congress should work to "fix" the program rather than author a replacement. 

Republicans have often struggled to unite around a solution to shortcomings in the U.S. immigration system, and the party is struggling to appeal to the U.S.'s growing Latino demographic. 

But Senator Lindsey Graham said he is supportive of Trump's decision, adding that lawmakers "will work to find a legislative solution" to the problems faced by DACA recipients, often known as "Dreamers".

"I have always believed DACA was a presidential overreach," he said in a statement. "However, I equally understand the plight of the Dream kids who -- for all practical purposes -- know no country other than America."

Only about 30 percent of Hispanics have voted for Republican candidates in the last three presidential elections, and former Republican Party head Reince Priebus has consistently urged his party to engage Latinos. 

But when the Republican Party nominated Trump, who infamously called Mexican immigrants "rapists" and "criminals" last year, those efforts were dealt a major blow. 

Outside of the White House, hundreds gathered in opposition to Trump's action, calling it a move that further heightens divisions in the country.

“This isn’t what our country is about,” said Vickie Sealey, a 58-year-old resident of neighboring Alexandria, Virginia. “Throughout it’s history we’ve always found a way to allow people to flourish and become Americans, and this is so contrary to anything I’ve been brought up to believe in.”

 For Sharice Davids, a 37-year-old Ho Chunk Native American from Wisconsin, Trump's action signaled a further commitment to dividing the nation.

“As an indigenous person from this land, it makes me sad that our country has progressed to where it’s at right now when it seemed like we were starting to move to a more unified country,” she said.

AA