The State Department is now requiring visa applicants to submit information about their social media accounts as part of a more extensive screening process that will affect about 15 million foreigners seeking to enter the United States each year.

The new requirement, which went into effect last Friday, applies to virtually all applicants for immigrant and nonimmigrant visas, including those who want to come to the U.S. for business or education. The policy follows a directive from the White House in 2017 asking the State Department to explore “extreme vetting” standards and procedures in the interests of national security.

“National security is our top priority when adjudicating visa applications, and every prospective traveler and immigrant to the United States undergoes extensive security screening,” the State Department said in a statement. “We are constantly working to find mechanisms to improve our screening processes to protect U.S. citizens, while supporting legitimate travel to the United States.”

According to the Washington Post, the new visa application forms list a number of social media platforms like Facebook, Twitter and Instagram, and require the applicant to provide any account names they have used on them over the previous five years. Applicants are also asked for all telephone numbers and email addresses they have used during the five-year timeframe.

Information provided by visa applicants is already checked against terrorism watch lists and databases. Applicants must also appear for an in-person interview with a State Department consular officer who is trained to look for red flags in their application. They must show proof that a return ticket has been purchased and that they have a place to stay in the U.S., answer a series of biographic questions and have their photos and fingerprints taken.

Association and travel industry leaders are concerned that the new social media requirements could discourage foreigners from planning trips to the U.S. for business or pleasure.

“Individuals from non-Visa Waiver Program countries already undergo a comprehensive, multi-layered screening process to obtain a temporary visa to enter the U.S. for tourism or business purposes,” said ASAE President and CEO John Graham. “Adding the additional scrutiny of social media accounts to an already rigorous set of vetting standards could have a chilling effect on inbound travel to the United States.”

Data analyzed by the U.S. Travel Association suggests that the U.S. is missing out on the lucrative global travel market. According to the Leading Travel Index, long-haul arrivals to the U.S. last year grew at half the pace of the international market worldwide – 3.5% versus 7%.