The US supreme court has refused to expand the scope of President Donald Trump's travel ban, thereby exempting from the order grandparents of American citizens from six Muslim-majority countries.

In a decision on Wednesday, the country's highest court said that Trump's ban must allow exemptions for family members, including grandparents.

The decision comes after a Hawaii court had earlier ruled that exemptions from the controversial ban should include grandparents, grandchildren, brothers-in-law, sisters-in-law, aunts, uncles, nieces, nephews and cousins.

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But in a partial win for Trump, the court also decided to put on hold part of the judge's ruling that would have allowed more people to enter the United States under a separate ban on refugees.

The brief order said its decision is temporary while the San Francisco-based 9th US Circuit Court of Appeals considers a separate appeal on the same issue.

The supreme court last month said that the 90-day ban on travellers from Iran, Somalia, Sudan, Syria and Yemen could be partially implemented.

But the order allowed for exemptions for visa applicants who could prove a "close familial relationship" with people in the US.

The ban came into partial effect under those conditions on June 29.

The supreme court is to hear the broad legal challenge to the ban during its October term.

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Hawaii, one of the several states fighting the travel ban since Trump first announced it in January, filed a court motion arguing that grandparents and grandchildren were by all measures also "close family".

Hawaii Attorney General Doug Chin welcomed the supreme court's ruling on travellers.

"This confirms we were right to say that the Trump Administration over-reached in trying to unilaterally keep families apart from each other," he said in a statement.

Added Omar Jadwat, director of the Immigrants' Rights Project at the American Civil Liberties Union activist group:

"Given an inch, the Trump Administration has tried to take a mile in implementing the ban. That is cruel, unnecessary, and unlawful," he said in a statement.

"We look forward to eradicating the entire Muslim ban, which is unconstitutional and repugnant to our most basic values as a country."

The White House and justice department had no immediate comment on the ruling.

The American Civil Liberties Union has called the ban "cruel, unnecessary, and unlawful" [EPA]

Source: News agencies