US President Donald Trump has signed a new executive order targeting so-called “birth tourism”, directing authorities to tighten scrutiny of foreign nationals suspected of travelling to the United States primarily to give birth.

The order instructs the Departments of State and Homeland Security to develop measures aimed at preventing temporary visitor visas from being used for the purpose of obtaining US citizenship for children born in the country.

Under the directive, visa applicants suspected of misrepresenting the purpose of their travel could face increased scrutiny, while those involved in organised birth-tourism schemes could have their visas revoked or face other immigration consequences.

The Trump administration argues that birth tourism exploits temporary visa categories and allows foreign nationals to obtain long-term immigration benefits through their children. The White House said the policy is intended to ensure that non-immigrant visas are used only for their lawful purposes.

The move comes alongside a separate executive order seeking to narrow birthright citizenship in specific circumstances. The administration's broader attempt to restrict birthright citizenship has already faced major legal challenges, with the Supreme Court recently rejecting Trump's earlier, broader approach.

The latest measures are expected to face further legal challenges from civil rights and immigration groups, who argue that executive action cannot override the citizenship protections contained in the 14th Amendment.