The U.S. Customs and Border Protection (CBP) proposed a rule on Dec. 10, published in the Federal Register, that would require travelers from visa waiver countries and regions to provide their social media history for the past five years when applying for entry to the United States.

The proposal affects visitors from dozens of countries, including most European nations, Australia, New Zealand, South Korea, and Japan, who enter the U.S. through the Electronic System for Travel Authorization (ESTA).

Since January, the U.S. government has stepped up efforts to combat illegal immigration and tightened scrutiny of visa applicants and holders. The U.S. State Department said on Dec. 9 that it had revoked 85,000 visas since January, more than double the number from the previous year, according to officials cited by U.S. media.