Visa holders from seven majority-Muslim countries who were turned away from the United States due to President Donald Trump's travel ban are hoping to make it through a narrow window opened by legal challenges.

A federal appeals court denied early Sunday the Justice Department's request for an immediate reinstatement of President Donald Trump's ban on accepting certain travellers and all refugees.

The U.S. government suspended enforcement of President Donald Trump's refugee and immigration ban and scurried to appeal a judge's order, plunging the new administration into crisis.