The US State Department has begun to require almost all visa applicants to submit information about their social media accounts and other personal details.
Officials say the new rule is an anti-terrorism measure, but critics have voiced serious concerns about free speech.
Applicants for US visas now have to submit the user names of their social media accounts, such as Twitter and Facebook, for the past five years.
The department is also asking for applicants’ phone numbers and email addresses for the same period.
Citizens of 38 countries and territories are allowed to make sightseeing or business trips to the US without a visa for up to 90 days.
But applicants planning longer stays, those from other countries and territories, and those who want to immigrate to the US need to obtain a visa.
US media say the change, which was proposed last year by President Donald Trump’s administration, is expected to affect 15 million people each year.
Department officials say the information will strengthen screening procedures by helping them to find out what kind of people applicants are.
The American Civil Liberties Union criticized the step for having a chilling effect on freedom of expression.
It says people are highly likely to self-censor online when they know the government is watching.