Some visitors to the United States may soon have to provide their social media history from the prior five years to enter the country, according to a new Trump administration proposal.

The proposal, posted on the Federal Register by US Customs and Border Protection, suggests travelers coming from countries that are part of a visa waiver program would need to give additional personal information as part of an electronic application.

The requirement would be for travelers using the Electronic System for Travel Authorization, or ESTA, as part of a visa waiver program for citizens from 42 countries, including the United Kingdom, New Zealand, Australia, Japan, Israel and Qatar, as well as many other European countries.

ESTA is an online application visitors from these countries use to travel to the US for under 90 days without a visa. Visitors using the online system are currently asked for information such as their passport and birth date, as well as any past criminal record.

The proposed changes to the visa waiver application include making provision of social media history mandatory and adding “high value data elements,” including the person’s phone numbers and email addresses over the prior five years, plus close family members’ names and birth dates, along with their birthplaces, residences and phone numbers over the prior five years.

A question about entering social media information was initially added to the application in 2016, with the section marked as “optional.”

“If an applicant does not answer the question or simply does not hold a social media account, the ESTA application can still be submitted without a negative interpretation or inference,” the CBP website now states.

The new proposal – open for public comment through February 9 – would make that information mandatory, though it’s unclear how it would impact those wishing to come to the United States. CNN has reached out to the Department of Homeland Security, which oversees CBP, for comment.

The changes would align with a broader push from President Donald Trump’s administration to overhaul the country’s legal immigration system, in addition to carrying out his long promised program of mass deportation for people in the country illegally.

The Trump administration over the past 11 months has made sweeping changes to nearly every facet of the immigration process, severely tightening every legal and illegal form of entry into the United States.

The administration also has placed heavy emphasis and scrutiny on the social media accounts of people in the US on student visas.

In June, the State Department told embassies and consulates they may vet applicants for student visas for “hostile attitudes towards our citizens, culture, government, institutions, or founding principles.”

According to those guidelines, applicants are asked to set their profiles to public, and lack of an online social media presence could be seen as a negative that may be held against them in the application process.