US president Donald Trump’s travel ban has been partly reinstated with a full hearing to follow in the autumn.
The Supreme Court will then decide whether the 90-day ban on people travelling to the US from Iran, Libya, Somalia, Sudan, Syria and Yemen will be enforced.
Until then, people entering the US from one of the six countries “who lack any bona fide relationship with a person or entity” in the country will remain barred.
Trump said the ban will come in effect within 72 hours of the court’s decision.
The Supreme Court said in Monday's decision: "In practical terms, this means that [the executive order] may not be enforced against foreign nationals who have a credible claim of a bona fide relationship with a person or entity in the United States.
"All other foreign nationals are subject to the provisions of [the executive order]."
The ruling also said it would permit a 120-day ban on all refugees entering the US to go into effect.
Last month, Trump suffered a setback when an appeals court upheld a ruling blocking the move. Judges found the executive order violated existing immigration legislation.