Donald Trump has hit out at the "so-called judge" who halted his travel ban, promising to overturn the "ridiculous" ruling.
He tweeted that the decision "essentially takes law enforcement away from our country".
In another post, he added: "When a country is no longer able to say who can, and who cannot, come in out, especially for reasons of safety security - big trouble!"
It comes after a ruling by a federal judge halted President Trump's temporary ban on people from seven Muslim-majority countries entering the US.
The ban has proved massively controversial and about 60,000 visas have been cancelled as a result.
But following the court ruling the US State Department said: "We have reversed the provisional revocation of visas.
"Those individuals with visas that were not physically cancelled may now travel if the visa is otherwise valid."
President Trump justified the ban by saying it would stop terrorism - even though no American has died as a result of a terrorist act by someone from one of the seven countries on US soil.
He also tweeted on Saturday that some Middle Eastern countries agreed with the ban because "they know if certain people are allowed in it's death destruction!"
Some airlines have started to allow people from the seven countries back onto US-bound flights after the judge's ruling.
Qatar Airways was the first to announce it would again open planes to passengers from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen.
Iberia, Air France, Etihad and Lufthansa followed suit.
An Iranian baby due to have life-saving heart surgery will also now be allowed in after her family's visa appointment was cancelled earlier this week.
President Trump's ban - which also stopped refugees from entering the US - was stopped in its tracks by Judge James Robart in Seattle.
The case was brought by the states of Washington and Minnesota.
Washington's lawyers said it had suffered harm because of the ban - for example because students and staff at its universities were stuck abroad.
Amazon.com and Expedia, both based in the state, also argued the restrictions were harming their businesses.
President Trump's order should be "based in fact, as opposed to fiction" for it to be constitutional, said Judge Robart.
He agreed that Washington state had demonstrated "immediate and irreparable injury" because of the ban and made it clear his ruling applied across the country.
The White House wants to reinstate the ban and said it would apply for an "emergency stay" of the order "at the earliest opportunity".
Meanwhile, protesters took to the streets of London on Saturday to vent their anger at a ban that many believe is racist, unfair and divisive.