Compliments of BBC
The late night ruling means the travel ban will remain suspended until the full case has been heard.
The court gave the White House and the states challenging it a deadline of Monday to present more arguments.
Two states argued that the travel ban, affecting people from seven mainly-Muslim countries, was unconstitutional.
In its appeal, the Justice Department said Judge James Robart had overreached by “second guessing” the president on a national security matter.
It also argued that only the president could decide who can enter or stay in the US.
n Friday’s case, the Justice Department had argued that states did not have the authority to challenge a presidential executive order.
Lawyers for the states of Washington and Minnesota had argued that the ban was unconstitutional because it denied people with valid entry documents the right to travel without due process.
It also violated freedom of religion rights by appearing to target Muslims, they said.
What happens now – BBC’s Anthony Zurcher, Washington
The next step is for briefs to be filed by both sides for a formal review of Judge Robart’s suspension on Monday. The Justice Department could have appealed directly to the Supreme Court on an emergency basis, but it chose not to since the appeal court is moving fairly quickly.
If the appeal court decides the stay is valid – perhaps as early as next week – then a Supreme Court appeal is almost certain.
In the meantime, everything is on hold. US immigration processes continue as they did before Mr Trump issued his executive order.
If it looks like this is bogging down, the president might eventually decide to modify the order rather than try to defend its legality. That’s probably the most prudent course, but he’s a stubborn man.