According to a new initiative being promoted by the Trump administration, some travelers to the United States may be required to provide details of their social-media activity from the past five years as a condition for receiving entry approval.

The proposal, published in the Federal Register by the U.S. Customs and Border Protection agency, stipulates that visitors from countries participating in the Visa Waiver Program will be required to provide additional personal information when completing the online application.

The requirement is intended for users of the ESTA system, which is used by citizens of 42 countries to enter the United States for less than 90 days without a visa. These countries include the United Kingdom, Israel, Australia, New Zealand, Japan, Qatar, and various European nations.

Currently, ESTA applicants must enter basic details such as passport number, date of birth, and criminal history. The proposed change would add a requirement to submit social-media account history, along with other information considered relevant, including phone numbers and email addresses from the past five years, as well as details about close family members: names, dates of birth, places of residence, and phone numbers.

The option to add social-media details has appeared on the form since 2016 as a voluntary field. According to the Customs and Border Protection agency, applicants who do not answer the question or who do not have any social-media accounts may still submit their application without it being interpreted negatively.