President Donald Trump signed a new proclamation on Wednesday barring travel to the U.S. from 12 countries:

“Afghanistan, Myanmar, Chad, Congo, Equatorial Guinea, Eritrea, Haiti, Iran, Libya, Somalia, Sudan, and Yemen”

citing national security concerns.

The ban, effective immediately, blocks most citizens from these nations, with limited exemptions for visa holders, green card holders, and certain special cases like Afghan allies. Additionally, seven other countries—Burundi, Cuba, Laos, Sierra Leone, Togo, Turkmenistan, and Venezuela—face partial restrictions on visas and immigration.

Trump justified the order by referencing a recent attack in Colorado, arguing that weak vetting endangers national security. He vowed to prevent Europe’s migration-related security issues from reaching the U.S. Legal experts note this ban is more carefully crafted than the 2017 version, as it follows an internal review and cites specific security risks, such as poor data-sharing or high visa overstay rates.