US President Donald Trump said Friday he is considering drafting a new order to ban migrants from majority-Muslim nations after his initial decree fell afoul of the law.

Insisting that he has the law on his side despite two defeats in federal court in quick succession, Trump said security concerns may necessitate a quicker response than legal channels would allow.

“The unfortunate part is that it takes time statutorily, but we will win that battle. We also have a lot of other options, including just filing a brand new order,” he said, adding that any action would not come before next week.

The statement represents an embarrassing climbdown for Trump, who has insisted that the order was well drafted and who has nevertheless vowed to fight on in the courts.

“We need speed for reasons of security, so it very well could be,” Trump said when asked if his plan was to have a new measure drafted.

Trump said Friday at a joint press conference with visiting Japanese Prime Minister Shinzo Abe that as president, he has learned of “tremendous threats to our country”.

“We'll be going forward and continuing to do things to make our country safe. It will happen rapidly,” he told reporters.

“We will not allow people into our country who are looking to do harm,” he said. “We will allow lots of people into our country that will love our people and do good for our country.”

'Whatever is necessary'

Trump's executive order issued in late January summarily denied entry to all refugees for 120 days, and travellers from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen for 90 days. Refugees from Syria were blocked indefinitely.

The White House has not provided any evidence to support Trump's view that a ban on travellers from the seven countries was urgently needed.

An appellate court decided unanimously on Thursday to maintain a block on Trump's order put in place by a lower court judge a week before.

The debacle has raised questions about the competence of Trump's White House in working through the practical and legal implications of the order.

The property mogul-turned-president was forced to sack the acting attorney general — an Obama administration holdover — after she refused to defend the order.

After first suggesting a quick appeal to the Supreme Court was off the table, US officials reversed course, insisting a legal challenge had not been dropped, including a possible motion to the high court.

“We're keeping all our options open,” one official said.

Nevertheless, an appeal on the temporary freeze in the lower courts now seems unlikely.

Earlier Friday, Trump vowed to do “whatever is necessary to keep our country safe”.

“We'll be doing something very rapidly having to do with additional security for our country. You'll be seeing that sometime next week,” the president said.

“In addition we will continue to go through the court process, and have no doubt we'll win that particular case,” he said.

'Disgraceful'

The measure — given with no notice — set off detentions of incoming travelers, protests at airports and international condemnation until a federal judge in Seattle stepped in and suspended the order a week later.

In upholding the suspension, the US court of appeals in San Francisco said Thursday the government had provided no evidence that any alien from the countries named in the order had carried out a terrorist attack on US soil.

“We hold that the government has not shown a likelihood of success on the merits of its appeal, nor has it shown that failure to enter a stay would cause irreparable injury,” the three-judge appellate panel ruled.

Trump's initial reaction came minutes later on Twitter: “SEE YOU IN COURT, THE SECURITY OF OUR NATION IS AT STAKE!” He followed up early Friday with a tweet calling the court's ruling "a disgraceful decision!"