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.

Trump also tied the new ban to a terrorist attack in Boulder, Colorado, saying it underscored the dangers posed by some visitors who overstay visas. U.S. officials say the man charged in the attack overstayed a tourist visa. He is from Egypt, a country that is not on Trump’s restricted list.