Some European countries, as well as Canada, are warning their citizens who travel to the United States to strictly follow the country’s entry rules or risk detention as the Trump administration cracks down on immigration enforcement.

Denmark, the United Kingdom, Germany, Finland and Canada have revised their guidelines at a time when some travelers from these countries have been detained by immigration officials.

Here is what to know about the advisories.

Why are these countries issuing warnings?

The heightened advisories come after citizens from European countries have been detained and deported by immigration officials while traveling to the United States. Some of the warnings also note that the State Department has also suspended its policy allowing transgender, intersex and nonbinary people to update the sex field on their passports — eliminating the X marker as an option.

“We will enforce visa rules and other conditions of entry,” a State Department spokesperson told NPR on Saturday. “Prohibiting travel into the United States by those who […]