A Trump administration travel ban that severely restricts the entry of nationals from Haiti, Cuba, and Venezuela into the United States starts Monday, and it’s yet unclear about how the policy will affect operations at Miami International Airport.

President Trump’s new ban on travel to the United States by citizens from a dozen countries took effect Monday with relative calm, as some travelers with valid visas reported extra scrutiny at American airports before being allowed entry.

The new proclamation, which Trump signed last week, applies to citizens of Afghanistan, Myanmar, Chad, the Republic of Congo, Equatorial Guinea, Eritrea, Haiti, Iran, Libya, Somalia, Sudan and Yemen.