Donald Trump has announced he plans to terminate the right to citizenship for babies born on US soil to non-citizens.
The US president, who is taking an increasingly hard-line stance on immigration, said the "process" to end birthright citizenship by executive order is underway, and denied such a fundamental change would need the input of congress.
"It was always told to me you need a constitutional amendment," Mr Trump told Axios on HBC. "Guess what, you don't."
"You can definitely do it with an act of congress, but now they're saying I can do it just with an executive order," the president continued.
Asked if he had consulted White House lawyers about such a contentious move, Mr Trump said he had and that it was "in the process, and it will happen".
Defending his stance, Mr Trump falsely claimed the US was the "only country in the world" that permits birthright citizenship. More than 30 countries allow unconditional citizenship to babies born within their borders, including most of the Americas.
"A person comes in, has a baby, and the baby is essentially a citizen of the United States for 85 years with all of those benefits. It's ridiculous, it's ridiculous and it has to end," he said.
Earlier this month, Michael Anton, a former Trump administration official, claimed in a Washington Post op-ed it was "absurd" that "simply being born within the geographical limits of the United States automatically confers US citizenship".
Any move by Mr Trump to end birthright citizenship, however, would not only spark fury among opponents, it will almost certainly spark legal challenges that would force the courts to decide on its constitutionality.
Under the Immigration and Nationality Act, US citizenship is granted to any person born on US soil, and ultimately stems from the Fourteenth Amendment of the American constitution.
The 1868 amendment states: "All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside."
Mark Krikorian, director at think tank the Center for Immigration Studies, said if implemented, the presidential order would eventually reach the supreme court, whose judges would have to rule on the meaning of "subject to the jurisdiction".
Barack Obama's former ethics chief, Norm Eisen, warned the US had never before seen a president "so willing to trample our laws".
"Probably a pre-election gimmick, but fortunately we have courts - see you there sir if you dare try this," Mr Eisen wrote on Twitter.
Mr Trump's announcement comes just a week before the US midterm elections, which Republicans are increasingly trying to cast as a referendum on immigration.
On Monday evening, the president told Fox News asylum seekers who illegally cross into the US from Mexico will be kept in "very nice" tents.
Railing against a migrant caravan heading for America’s southern border, Mr Trump said his administration is going to build tent cities in preparation for what he described as an “invasion” of the country.
The White House has been contacted for comment.
