WASHINGTON (AP):

Rebuffed in its bid for a quick reversal, the White House said on Sunday that it expected the courts to reaffirm President Donald Trump's executive power and reinstate a ban on refugees and travellers from seven predominantly Muslim countries from entering the United States.

The case promised to extend into Monday at least, when fresh legal filings were due, and observers had no doubt the Supreme Court ultimately will have a say.

The San Francisco-based 9th US Circuit Court of Appeals, in a brief order overnight, denied the administration's request to set aside a Seattle judge's ruling that put a temporary hold on the ban nationwide.

The lawsuit by Washington state and Minnesota said Trump's order harmed residents and effectively mandated discrimination. Their lawyers had until 2:59 a.m. EST Monday to submit briefs opposing the government's request. The Justice Department then had a 6 p.m. EST deadline to respond.

"We'll accomplish the stay and will win the case on the merits," Vice-president Mike Pence said.

Members of Trump's Republican Party scolded him for Twitter attacks on US District Court Judge James Robart, appointed by President George W. Bush, and lawmakers accused Trump of stepping over the line that separates the executive from the judiciary. To Trump, Robart is a "so-called judge" whose "ridiculous" ruling "will be overturned".

"The president can criticise anybody he wants," Pence said, adding that he believes the American people "find it very refreshing that they not only understand this president's mind, but they understand how he feels about things."

At issue is the legality of a presidential action undertaken in the name of national security. Whatever the outcome and however the case drags on, a president who was used to getting his way in private business is finding, weeks into the jobs, obstacles to quickly fulfilling one of his chief campaign pledges.

"The president is not a dictator," said Senator Dianne Feinstein. "He is the chief executive of our country. And there is a tension between the branches of government."

The government had told the appeals court that the president alone has the power to decide who can enter or stay in the United States, an assertion that appeared to invoke the wider battle to come over illegal immigration.

Congress "vests complete discretion" in the president to impose conditions on entry of foreigners to the United States, and that power is "largely immune from judicial control", according to the court filing.