WASHINGTON (REUTERS) - US President Donald Trump said on Wednesday (Aug 21) that his administration was seriously looking at ending the right of citizenship for US-born children of noncitizens and people who immigrated to the United States illegally.

"We're looking at that very seriously, birthright citizenship, where you have a baby on our land, you walk over the border, have a baby - congratulations, the baby is now a US citizen... It's frankly ridiculous," Trump told reporters outside the White House.

Trump has made cracking down on immigration a central plank of his presidency and re-election campaign, but many of the administration's sweeping rule changes and executive orders have been stymied by the courts.

The Republican president had told Axios news website in October 2018 that he would end "birthright citizenship" through an executive order.

Experts have said such a move would run afoul of the US Constitution.

The Constitution's 14th Amendment, passed after the Civil War to ensure that black Americans had full citizenship rights, granted citizenship to "all persons born or naturalised in the United States."

It has since routinely been interpreted to grant citizenship to most people born in the United States, whether or not their parents are American citizens or legally living in the United States.