President Donald Trump has banned citizens of 12 countries from entering the United States and restricted access for those from seven others, citing national security concerns in resurrecting and expanding a hallmark policy from his first term that will mostly affect people from Africa and the Middle East.

The travel ban results from a Jan. 20 executive order Trump issued requiring the departments of State and Homeland Security and the director of national intelligence to compile a report on “hostile attitudes” toward the U.S. and whether entry from certain countries represented a national security risk.