WASHINGTON — President Trump on Sunday issued a new order banning almost all travel to the United States from seven countries, including most of the nations covered by his original travel ban, citing threats to national security posed by letting their citizens into the country.
Starting next month, most citizens of Iran, Libya, Syria, Yemen, Somalia, Chad and North Korea will be indefinitely banned from entering the United States, Mr. Trump said in a proclamation released Sunday night. Citizens of Iraq and some groups of people in Venezuela who seek to visit the United States will face restrictions or heightened scrutiny.
Mr. Trump’s original travel ban, which caused chaos at airports earlier this year and set off a furious legal challenge to the president’s authority, expired on Sunday even as the Supreme Court is set to hear arguments about its constitutionality on Oct. 10. The new bans will take effect Oct. 18.
“As president, I must act to protect the security and interests of the United States and its people,” Mr. Trump said in the proclamation, which White House officials said had the same force as an executive order. He added that the restrictions will remain in effect until the governments of the affected nations “satisfactorily address the identified inadequacies.”
Officials described the new order as a much more targeted effort than the president’s earlier one. Each of the countries will be under its own set of travel restrictions, though in most cases citizens of the countries will be unable to emigrate to the United States personally and most will be barred from coming to work, study or vacation in America.
Iran, for example, will still be able to send its citizens on student exchanges, though such visitors will be subject to enhanced screening. Certain government officials of Venezuela and their families will be barred from visiting the United States. Somalis will no longer be allowed to emigrate to the United States, but may visit with extra screening.
The president’s announcement comes after the administration conducted a worldwide, 90-day review of the security measures in place in other countries to prevent terrorists or criminals from entering the United States by applying for a tourist, work or education visa.
Mr. Trump called for the review — and a temporary ban on travel from several majority-Muslim countries — just days after being inaugurated. But a fierce legal challenge to the travel ban delayed the security assessment until the summer.
Officials said last week that most nations already met new, minimum standards for identifying and screening potential travelers and sharing investigative information with law enforcement agencies in the United States. Some nations that initially fell short of those standards agreed to implement changes to avoid travel restrictions.
But several countries either failed to meet those standards or flatly refused, officials said. Homeland Security officials recommended to Mr. Trump in a report last week that he impose the new travel restrictions on the residents of those countries.
Mr. Trump’s original travel ban prevented all travel from citizens of seven countries: Iraq, Iran, Libya, Somalia, Sudan, Syria and Yemen. Iraq was later removed from a second version of the travel ban in March after American officials said it had improved its ability to screen passengers and share information with the United States.
Homeland Security officials had described the previous ban as a temporary pause on travel from certain countries to allow for the review of security measures.
By contrast, the new travel restrictions will be in place indefinitely, officials said. The United States will consider lifting the restrictions on those countries affected only if they meet the new minimum standards, they said.
The president’s announcement could have a dramatic impact on the legal challenge to the previous travel ban, which is under consideration by the Supreme Court after the administration appealed lower court rulings that said the ban was unconstitutional and a breach of Mr. Trump’s authority.
Oral arguments in the case are scheduled for Oct. 10, but legal experts said that parts of the case could be moot because of the president’s decision to end that travel ban. Other parts of the case, including restrictions on refugees coming into the United States, were not affected by Sunday’s announcement.
But lawyers who filed challenges to the president’s previous travel ban left open the possibility that they would also challenge the new restrictions.
“This is an apparent effort to paper over the original sin of the Muslim ban, especially when just last week Trump said he wanted a ‘larger, tougher, more specific’ ban,” said Anthony D. Romero, the executive director of the American Civil Liberties Union.
The original travel ban was met with angry denunciations from civil rights activists and others who said the president was violating the Constitution by specifically targeting Muslims. They also criticized Mr. Trump’s administration for abruptly imposing the ban, causing chaos at airports as visitors were turned away by border agents who had not been briefed on the new policy.
Administration officials said on Friday that the new policy was the result of months of deliberation that included the State Department, the Department of Homeland Security, the White House and other agencies involved in security and the border.