The unanimous ruling, from a panel of three judges in San Francisco, could pave the way for a showdown in the Supreme Court.

 

However, the appeals court justices expressed doubt that Mr Trump's government would be successful if it launched another appeal.

 

Unabated, Mr Trump tweeted: "SEE YOU IN COURT, THE SECURITY OF OUR NATION IS AT STAKE!"

 The US Justice Department was more measured in its response, and a spokeswoman said it was "considering its options".

 

In their judgment, they said the US Justice Department had not offered "any evidence" of national security concerns which had justified banning migrants, visitors and refugees from seven Muslim-majority countries.

 

The judges concluded that the government had provided no evidence that any citizen from Iraq, Iran, Libya, Somalia, Sudan, Yemen and Syria had perpetrated an attack on American soil.

 

In addition, no evidence was offered which explained the urgent need for his executive order to take effect immediately.

 

Lawyers from Washington state and Minnesota - which mounted the legal challenge against Mr Trump - had offered compelling evidence that even a temporary reinstatement of the travel ban would cause harm, and raised serious allegations of religious discrimination.

 

The ruling means migrants, visitors and refugees from the affected countries can continue to travel to the US if they have valid visas or green cards - something which Mr Trump had attempted to stop with his executive order.

 

In its arguments, the Justice Department had insisted that the President had the constitutional power to restrict entry to the US - and that the courts should not attempt to second-guess his determination that such measures were needed to prevent terrorism on American soil.

 

Mr Trump's executive order had been temporarily suspended nationwide by Judge James Robart in Seattle last week.

 

Following that ruling, the President branded Mr Robart's ruling as "ridiculous" - and described him as a "so-called judge".