(WASHINGTON) — The Trump administration is imposing new visa rules aimed at restricting “birth tourism,” in which women travel to the United States to give birth so their children can have U.S. citizenship. The regulations, which take effect Friday, address one of President Donald Trump’s main political priorities.

The regulations seek to chip away at the number of foreigners who take advantage of the constitutional provision granting“birthright citizenship” to anyone born in the United States, a particular peeve of Trump’s. Under the new rules, pregnant applicants will be denied a tourist visa unless they can prove they must come to the U.S. to give birth for medical reasons and they have money to pay for it or have another compelling reason — not just because they want their child to have an American passport.

Officials said that consular officers will not be asking all female visa applicants of child-bearing age whether they are pregnant or intend to get pregnant. Rather, they said consular officers would ask the question only if they had reason to believe the applicant is pregnant and likely or planning to give birth in the U.S.