The State Department on Thursday unveiled new rules that could make it more difficult for pregnant foreign nationals to travel to the United States using tourist visas, citing security concerns.
The rules, which will become effective on Friday, are an attempt to crack down on "birth tourism," or the practice of giving birth in the United States in order to obtain U.S. citizenship for a child. They apply to B visas, or those issued to nonimmigrants.
"Closing this glaring immigration loophole will combat these endemic abuses and ultimately protect the United States from the national security risks created by this practice," White House press secretary Stephanie Grisham said in a statement. "It will also defend American taxpayers from having their hard-earned dollars siphoned away to finance the direct and downstream costs associated with birth tourism."
"The integrity of American citizenship must be protected," she said.
The Trump administration has sought to limit immigration to the United States, and President Donald Trump has been particularly critical of birthright citizenship, or the right of those born in America to citizenship. The 14th Amendment to the Constitution grants citizenship to "all persons born or naturalized in the United States."
Activists criticized the administration's move. Adrian Reyna, the strategy director of United We Dream, a nonprofit immigration group, said in a statement that "Trump continues to find new ways to try to divide and attack families."
"Discriminating against pregnant individuals by blocking them from coming to visit the country does nothing but keep people from their loved ones," Reyna said. "This rule is based on Trump's racist fixation on ending birthright citizenship and essentially stopping the movement of people into this country."
There are no official figures documenting how many foreigners travel to the U.S. specifically to give birth, though the State Department cited reporting from U.S. embassies and consulates it said documented an increase in the trend.
The Center for Immigration Studies, a conservative group that advocates for stricter immigration laws, estimates that there were 20,000 to 25,000 births to women in the country temporarily on tourist visas between the second half of 2016 and the first half of 2017. Jeremy Neufeld, an expert at the Niskanen Center, had critiqued CIS' estimate and said the number could be fewer than 2,000.
It's not clear how consular officials will determine whether individuals seeking to travel to the U.S. are pregnant. The rule calls for officials to reject the visa applications of individuals whose "primary purpose" is obtaining U.S. citizenship for a child by giving birth.
"The final rule addresses concerns about the attendant risks of this activity to national security and law enforcement, including criminal activity associated with the birth tourism industry, as reflected in federal prosecutions of individuals and entities involved in that industry," the department said.
The new rules also tighten the restrictions on traveling to the U.S. to seek medical treatment.
The department said it will deny visas to those seeking medical treatment if they are unable to establish "to the satisfaction of a consular officer" that there exists a legitimate medical reason for treatment and that a practitioner or facility in the U.S. has agreed to provide it.
The visa applicant must also prove that he or she "has the means and intent" to pay for the medical treatment and related expenses, according to the new rules.
Correction: This story was revised after the Center for Immigration Studies issued a correction to its figures on March 13. The group revised its figures to 20,000 to 25,000 from 33,000.
— CNBC's Yelena Dzhanova contributed to this report.