Donald Trump has suffered the biggest defeat of his short presidency as a court refused to reinstate his executive order banning refugees and restricting travel to the United States from seven Muslim-majority countries.

Federal and local law enforcement agencies have increased protection for the judges involved, amid threats against more than one of them, as tensions run high over the decision.

Furious at the unanimous decision by a panel of three judges to uphold the halt placed on his travel ban, Mr Trump indicated he would now make good on a pledge to take the case to the Supreme Court.

“See you in court, the security of our nation is at stake!” he tweeted in capital letters.

In response, Washington Gov. Jay Inslee, a Democrat who leads one of the states that challenged the ban, said: "Mr. President, we just saw you in court, and we beat you."