US President Donald Trump has said the latest federal court ruling against his proposed travel ban comes at a "dangerous time".
Mr Trump tweeted: "Well, as predicted, the 9th Circuit did it again - Ruled against the TRAVEL BAN at such a dangerous time in the history of our country. S.C."
"S.C." may refer to the Supreme Court, where Mr Trump has vowed to take his travel ban fight.
The San Francisco-based 9th US Circuit Court of Appeals has refused to reinstate Mr Trump's executive order banning travellers from six mostly Muslim countries.
A three-judge panel said the administration failed to show that blocking citizens from Iran, Libya, Somalia, Sudan, Syria and Yemen was needed to protect the US.
The court also found that the president's order ran afoul of an immigration law that prohibits discrimination on the basis of nationality.
The 4th US Circuit has also called Mr Trump's national security concerns an after-the-fact justification for a policy that was "steeped in animus and directed at a single religious group".
The Trump administration has asked the Supreme Court to immediately reinstate its ban on travellers from six mostly Muslim countries, saying the US will be safer if the policy is put in place.