Here is a closer look at why the administration says it is instituting full bans on foreign nationals traveling to the U.S. from 12 nations.

For people in countries like Afghanistan and Myanmar, the president’s order dimmed hopes for sanctuary in the United States.

Brazzaville, Equatorial Guinea, Eritrea, Haiti, Iran, Libya, Somalia, Sudan, and Yemen. Nationals from a further seven countries - Burundi, Cuba, Laos, Sierra Leone, Togo, Turkmenistan and Venezuela - will face partial travel restrictions.