President Donald Trump is reinstating a travel ban policy from his previous term. On Wednesday night, he signed a proclamation that will prevent people from a dozen specific countries from entering the United States.

The countries include Afghanistan, Burma, Chad, Republic of the Congo, Equatorial Guinea, Eritrea, Haiti, Iran, Libya, Somalia, Sudan and Yemen.

Besides the travel ban, which will come into effect at 12:01 a.m. on Monday, Trump also imposed increased restrictions on visitors coming from Burundi, Cuba, Laos, Sierra Leone, Togo, Turkmenistan, and Venezuela.

“I must act to protect the national security and national interest of the United States and its people,” Trump said in his proclamation.

This decision follows a January 20 executive order from Trump that tasked the departments of State and Homeland Security, along with the Director of National Intelligence, to prepare a report on countries with “hostile attitudes” toward the U.S. and assess if allowing entry from these nations poses a national security threat.

During his first term, Trump issued an executive order in January 2017 banning travel to the U.S. by citizens of seven predominantly Muslim countries – Iraq, Syria, Iran, Sudan, Libya, Somalia and Yemen.

It was one of the most chaotic and confusing moments of his young presidency. Travelers from those nations were either barred from getting on their flights to the U.S. or detained at U.S. airports after they landed. They included students and faculty as well as businesspeople, tourists and people visiting friends and family.

The order, often referred to as the “Muslim ban” or the “travel ban,” was retooled amid legal challenges, until a version was upheld by the Supreme Court in 2018.

The ban affected various categories of travelers and immigrants from Iran, Somalia, Yemen, Syria and Libya, plus North Koreans and some Venezuelan government officials and their families.

Trump and others have defended the initial ban on national security grounds, arguing it was aimed at protecting the country and not founded on anti-Muslim bias. However, the president had called for an explicit ban on Muslims during his first campaign for the White House.