The US Customs and Border Protection has started demanding that foreign travelers hand over Facebook, Twitter, and other social media account information upon entering the country, according to a report from Politico. The new policy follows a proposal laid out back in June and applies only to those travelers who enter the US temporarily without a visa through the Electronic System for Travel Authorization, or ESTA, process. The goal, the government says, is to “identify potential threats,” a spokesperson tells Politico.

Activists fear the policy could be a threat to human rights

The new policy went into effect on Tuesday, and the request is currently “optional.” It asks foreign travelers to “enter information associated with your online presence,” and offers a drop-down menu allowing participants to enter in account names for most major social networks, including LinkedIn and even Google+.

It’s unclear if the information collected can be immediately used to deny travelers entry into the US. However, the express purpose of the collection is to identify individuals with ties to terrorist groups. As it stands today, Customs and Border Protection says it will not deny entry to those that refuse to submit any social media information.

Still, the implementation of such a controversial policy has enraged human rights activists and technology companies. Members of both communities expressed concern when the policy was first proposed this past summer. At the time, industry lobbying group the Internet Association, which represents companies like Facebook and Google, joined with the ACLU to condemn the proposal for its potential free speech and privacy violations.

you can see the form for yourself here btw: https://t.co/GmDb4p6ROz



yes, it does say google plus and github lol https://t.co/QftMn3an3h — Tony Romm (@TonyRomm) December 22, 2016

These groups fear that the request for social media info, although voluntary, will urge members of marginalized groups from the Middle East and elsewhere to fill out the information for fear of being denied entry. It could then be highly scrutinized, activists say, without clear and transparent guidelines. The policy could also lead to potential abuses and even security risks as the information is collected and stored by the government.

This new form of data collection happens to arrive just one month before the inauguration of President-elect Donald Trump, who on Wednesday seemingly renewed his call for a ban on Muslims entering the US following the bus attack in Berlin. Just yesterday, it was also revealed that data-mining firm Palantir, which was co-founded by Trump advisor Peter Thiel, has worked with the US Customs and Border Protection to track immigrants and foreign travelers using a wide variety of data gleaned from law enforcement databases. Social media account information could aid in this process.