The U.S. Supreme Court on Wednesday granted a request by President Donald Trump's administration to fully enforce a new rule that would curtail asylum applications by Central American immigrants at the U.S.-Mexico border.

The court said the rule, which requires most immigrants who want asylum to first seek safe haven in a third country through which they traveled on their way to the United States, could go into effect as litigation challenging its legality continues.

The San Francisco-based 9th U.S. Circuit Court of Appeals on August 16 limited a federal judge's injunction blocking the rule to the nine Western states over which it has jurisdiction including the border states of California and Arizona. That had left open the possibility that the rule could be applied in the two other border states, Texas and New Mexico.

The American Civil Liberties Union (ACLU) and others who challenged the administration's policy in federal court said it violates U.S. immigration law and accused the administration of failing to follow the correct legal process in issuing the rule, which was unveiled on July 15.

California-based U.S. District Judge Jon Tigar in July issued a nationwide injunction blocking the rule before the 9th Circuit scaled it back.

The rule would bar almost all immigrants from applying for asylum at the southern border. It represents the latest effort by Trump's administration to crack down on immigration, a signature issue during his presidency and 2020 re-election bid.

Liberal Justice Sonia Sotomayor dissented the decision to lift the injunction by saying that the government's rule may be in significant tension with the asylum statute.

"It is especially concerning, moreover, that the rule the government promulgated topples decades of settled asylum practices and affects some of the most vulnerable people in the Western Hemisphere — without affording the public a chance to weigh in," said Sotomayor.

One of Trump's main objectives has been to reduce the number of asylum claims primarily by Central American migrants who have crossed the U.S.-Mexico border in large numbers during his presidency.

The rule would block nearly all families and individuals from countries like El Salvador, Honduras and Guatemala from entering the U.S. as asylum seekers after crossing through Mexico. The rule would keep asylum protections for Mexican citizens.

The rule drew legal challenges including from a coalition of groups represented by ACLU. They accused the administration of pursuing an "asylum ban" and jeopardizing the safety and security of migrants fleeing persecution and seeking safety in the United States.