President Trump's new ban on travel to the U.S. by citizens from 12 mainly African and Middle Eastern countries has taken effect amid rising tension over the president's escalating campaign of immigration enforcement.

President Donald Trump's order banning citizens of 12 countries aims to protect the US from "foreign terrorists." What are the reasons and who is exempt?

The travel ban forms part of Trump's policy to restrict immigration into the United States and is reminiscent of a similar move in his first term