(The Hill) — President Donald Trump signed a proclamation on Wednesday that bars individuals from 12 countries from entering the United States and that places additional travel restrictions on people from another seven countries.

The president cited national security concerns in announcing the ban, which officially takes effect at 12:01 a.m. on Monday.

The proclamation — which echoes a travel ban from Trump’s first term — makes exceptions for nationals from all 19 of those countries who are lawful permanent residents of the United States, existing visa holders and individuals whose entry serves U.S. national interests.

In a video posted online, Trump said that additional countries could be added to the list if new international threats arise at a later point.

“The list is subject to revision based on whether material improvements are made,” the president said. “And likewise, new countries can be added as threats emerge around the world, but we will not allow people to enter our country who wish to do us harm and nothing will stop us from keeping America safe.”

Here are the countries affected by the new proclamation:

12 countries banned:

• Afghanistan
• Burma
• Chad
• Republic of the Congo
• Equatorial Guinea
• Eritrea
• Haiti
• Iran
• Libya
• Somalia
• Sudan
• Yemen

7 countries restricted:

• Burundi
• Cuba
• Laos
• Sierra Leone
• Togo
• Turkmenistan
• Venezuela