US President Donald Trump signed a proclamation on Wednesday banning the nationals of 12 countries from entering the United States, saying the move was needed to protect against “foreign terrorists” and other security threats.

The countries affected are Afghanistan, Myanmar, Chad, Congo, Equatorial Guinea, Eritrea, Haiti, Iran, Libya, Somalia, Sudan and Yemen.

The entry of people from seven other countries: Burundi, Cuba, Laos, Sierra Leone, Togo, Turkmenistan and Venezuela, will be partially restricted. The travel restrictions were first reported by CBS News.

“We will not allow people to enter our country who wish to do us harm,” Trump said in a video posted on X. He said the list could be revised and new countries could be added.

The proclamation is effective on June 9, 2025 at 12:01 am EDT (0401 GMT). Visas issued before that date will not be revoked, the order said.

During his first term in office, Trump announced a ban on travelers from seven majority-Muslim nations, a policy that went through several iterations before it was upheld by the Supreme Court in 2018.

Former President Joe Biden, a Democrat who succeeded Trump, repealed the ban in 2021, calling it “a stain on our national conscience.”

Trump said the countries subject to the most severe restrictions were determined to harbor a “large-scale presence of terrorists,” fail to cooperate on visa security and have an inability to verify travelers’ identities, inadequate record-keeping of criminal histories and high rates of visa overstays in the United States.

“We cannot have open migration from any country where we cannot safely and reliably vet and screen those who seek to enter the United States,” Trump said.

He cited Sunday’s incident in Boulder, Colorado in which a man tossed a gasoline bomb into a crowd of pro-Israel demonstrators as an example of why the new restrictions are needed.

An Egyptian national, Mohamed Sabry Soliman, has been charged in the attack. Federal officials said Soliman had overstayed his tourist visa and had an expired work permit - although Egypt is not on the list of countries facing travel limits.

Somalia immediately pledged to work with the US to address security issues.

“Somalia values its longstanding relationship with the United States and stands ready to engage in dialogue to address the concerns raised,” Dahir Hassan Abdi, the Somali ambassador to the United States, said in a statement.

Trump’s directive is part of an immigration crackdown that he launched at the start of his second term. He previewed his plan in an October 2023 speech, pledging to restrict people from the Gaza Strip, Libya, Somalia, Syria, Yemen and “anywhere else that threatens our security.”

Trump issued an executive order on January 20 requiring intensified security vetting of any foreigners seeking admission to the US to detect national security threats. That order directed several cabinet members to submit a list of countries from which travel should be partly or fully suspended because their “vetting and screening information is so deficient.”

In March, Reuters reported that the Trump administration was considering travel restrictions on dozens of countries.