A federal judge has ordered the Trump administration to explain how it will enforce President Trump's executive order seeking to eliminate birthright citizenship.

Birthright citizenship automatically makes anyone born in the United States an American citizen, including children born to mothers in the country illegally. The right was enshrined soon after the Civil War in the Constitution’s 14th Amendment. The U.S. is among about 30 countries where birthright citizenship is applied.

President Donald Trump's administration will not deport children deemed ineligible for U.S. citizenship until his executive order curtailing birthright citizenship takes effect on July 27, a government lawyer said on Monday after being pressed by two federal judges.