Central American asylum seekers walk to a shelter in McAllen, Texas, June 20, 2018 (Veronica G. Cardenas/MySA)

Donald Trump is moving to end asylum for migrants entering the US.

Acting on one of Trump’s anti-immigrant lines before last Tuesday’s Congressional elections, the Administration invoked national security powers meant to protect the US against threats from abroad.

Trump is expected to announce on Friday which migrants will be affected, listing their home countries. The measure will go into effect on an emergency basis as soon as it is published in the Federal Register.

Current US asylum laws allow migrants fleeing persecution and violence to seek sanctuary by reporting to a US port of entry.

The Administration’s “zero tolerance” policy, announced in April, tried to curb the right. As children were separated from parents entering the US, some migrants were detained before they could reach a port of entry. Others were turned away, with officials saying the ports were full.

Trump’s order is likely to face an imediate legal challenge. Lawyers for immigration advocacy organizations said the step violates a founding principle of federal asylum that each person’s claim is judged on its merits.

The lawyers also said federal and international law mandates that the US must provide immigrants the opportunity to claim asylum.

“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.”

Trump is using the same authority invoked for his “Muslim Ban” to ban entry into the US for citizens from several predominantly Muslim countries.

The ban was first announced in January 2017, days after Trump’s inauguration. It was rejected by courts on several occasions, but a revised version finally cleared the Supreme Court last autumn.