President Donald Trump signed two executive orders Thursday aimed at what his administration calls "birth tourism," including one that seeks to expand the categories of people ineligible for birthright citizenship.

White House officials said the first order broadens the existing exceptions to birthright citizenship under the 14th Amendment. Examples discussed in the Oval Office included "alien enemies" of the United States, members of foreign terrorist organizations and certain people who lobby or act on behalf of foreign governments.

RELATED STORY | Supreme Court rejects Trump's bid to end birthright citizenship

The 14th Amendment guarantees citizenship to most people born in the United States, though limited exceptions already exist. The administration says the order expands those exceptions.

A second executive order targets so-called birth tourism, in which pregnant women travel to the United States on tourist visas to give birth so their children will obtain U.S. citizenship. White House officials acknowledged the practice is relatively uncommon but said the administration wants to prevent people from using tourist visas for that purpose.

Officials did not explain how they would determine whether a traveler intends to give birth in the United States. Reporters asked how immigration officials would decide whether someone is too far along in a pregnancy to enter on a tourist visa, but the administration did not provide details.

Instead, officials pointed to a provision of the Immigration and Nationality Act that allows the president to prescribe certain limitations and exceptions under existing immigration law.

The orders appear to be the administration's latest effort to limit birthright citizenship following a recent Supreme Court decision reaffirming that most people born in the United States are automatically U.S. citizens.