President Donald Trump’s administration, on Thursday rolled out a new rule that aims to limit “birth tourism” by women who enter the U.S. on tourist’s visa.

“Birth tourism’’ is intention of obtaining citizenship for their babies born on American soil.

According to Reuters, under the State Department regulation, which will take effect on Friday, pregnant women applying for visitor’s visa, could be required to prove they have a specific reason for travel beyond giving birth, such as a medical necessity.

Trump has criticised the right to citizenship for any person born in the U.S., which applies even to children born to tourists.

Scrapping that right would require a change in the U.S. Constitution as the country’s law does not bar foreign women from travelling to the U.S. to give birth.

A State Department official said in a statement that the new rule aims to address national security risks, including criminal activity associated with the industry for birth-related trips.

The final rule says consular officers must scrutinise female travellers to determine whether they might be pregnant, however does not explain how officers will make such determinations.

The State Department official said U.S. officials would not ask all female visa applicants if they were pregnant, or intended to be, but instead would only raise the issue if they had “a specific strong reason” to believe the sole purpose of the U.S. visit was to give birth.