Of the 12 countries from which travel is fully restricted, three are embroiled in bloody civil wars. Many of the other countries are also undergoing conflicts.

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.

President Trump on Wednesday signed a travel ban on 12 countries, primarily in Africa and the Middle East, reviving an effort from his first term to prevent large numbers of immigrants and visitors from entering the United States.