WASHINGTON — The Trump administration announced new immigration rules on Thursday that give President Trump vast new authority to deny asylum to virtually any migrant who crosses the border illegally, invoking national security powers meant to protect the United States against threats from abroad.
Officials declined to say who will be affected, but they indicated that the president will issue a proclamation on Friday. It is widely expected inside the government and by migrant advocates that Mr. Trump intends to deny asylum to members of Central American nations, some of whom are marching toward the United States in a caravan.
Administration officials said the new regulations — which draw upon the same authority that Mr. Trump used to ban travel from predominantly Muslim countries only days after his inauguration — give the president, and his successors, new power to deny asylum to any group of immigrants who cross the border illegally.
That assertion is certain to be challenged in court. Immigration advocates said it violates longstanding federal asylum law that is meant to judge each person’s asylum claim on its own merits. And they said the new rules conflict with treaties in which the United States pledged to accept asylum claims from migrants.
“The law is clear: people can apply for asylum whether or not they’re at a port of entry, and regardless of their immigration status,” said Omar Jadwat, the director of the American Civil Liberties Union’s Immigrants’ Rights Project. “The president doesn’t get to ignore that law, even if he dislikes it.”
Officials said the new rules will overhaul longstanding asylum laws that provide the opportunity for people fleeing persecution and violence in their home countries to seek sanctuary in the United States. The changes effectively close the option of asylum to those who do not enter the country legally at an official port of entry.
Once the president makes a proclamation identifying who is barred by the new regulations, those people would be immediately denied if they try to claim asylum. Officials said the migrants could apply for two other, smaller programs that are much less likely to allow them to stay.
Mr. Trump has fumed at his advisers for months about the surge of immigrants crossing into the United States from Mexico. During the past few weeks of the midterm election, the president became enraged by a caravan of several thousand migrants and ordered 5,000 active-duty troops to the border to prevent them from crossing.