President Donald Trump signed a proclamation on Wednesday banning travel from 12 countries, citing national security concerns.

The administration is imposing full restrictions on entry into the United States from nationals of Afghanistan, Burma, Chad, the Republic of the Congo, Equatorial Guinea, Eritrea, Haiti, Iran, Libya, Somalia, Sudan and Yemen.

Additionally, Trump is imposing partial restrictions on entry from nationals of seven other countries: Burundi, Cuba, Laos, Sierra Leone, Togo, Turkmenistan and Venezuela.

"As President, I must act to protect the national security and national interest of the United States and its people. I remain committed to engaging with those countries willing to cooperate to improve information-sharing and identity-management procedures, and to address both terrorism-related and public-safety risks," Trump wrote.

During Trump’s first term, he issued an executive order shortly after he was inaugurated in January 2017 banning travel to the U.S. by citizens of seven predominantly Muslim countries - Iraq, Syria, Iran, Sudan, Libya, Somalia and Yemen.

The order -- often referred to as the "Muslim ban" or the "travel ban" -- was challenged in the courts before it was eventually retooled, and a version was upheld by the Supreme Court in 2018.