U.S.-bound migrants were seizing the opportunity to enter the United States on Sunday after a federal appeals court in San Francisco denied the Trump administration request for immediate reinstatement of a controversial, temporary travel ban.

Judges William Canby, Jr., and Michelle Friedland gave no reason in their brief ruling, but ordered the states of Washington and Minnesota, which had filed suit to halt the ban, to provide a detailed explanation for their lawsuit by Monday. The Justice Department was ordered to file its response by Monday at 6 p.m. ET.

Cairo airport officials told the Associated Press that 33 U.S.-bound migrants from Yemen, Syria and Iraq boarded flights Sunday on their way to the United States.

President Trump ordered the travel ban Jan. 27, one week after his inauguration. The executive order suspended entry of all refugees to the U.S. for 120 days, halted admission of refugees from Syria indefinitely and barred entry for three months to residents from the predominantly Muslim countries of Iraq, Syria, Iran, Sudan, Libya, Somalia and Yemen.

The order immediately sparked anger and confusion across the nation as scores of incoming travelers were held up at U.S. airports and many more were halted from boarding flights bound for the U.S. Protests erupted at airports and city halls nationwide.

After days of legal wrangling, Judge James Robart, sitting in Seattle, issued the temporary restraining order Friday night that lifted the ban nationwide. The Justice Department appealed, claiming that "judicial second-guessing of the President" constitutes an "impermissible intrusion" into Trump's authority, the Justice Department said.

Trump was more succinct, tweeting that the "opinion of this so-called judge, which essentially takes law-enforcement away from our country, is ridiculous and will be overturned!"

Still, the State Department said it was restoring tens of thousands of canceled visas for foreigners and the Department of Homeland Security "suspended all actions" for enforcing the ban and instead began standard inspection of travelers.

"Because the ban was lifted by a judge, many very bad and dangerous people may be pouring into our country. A terrible decision," he tweeted.

The State department on Saturday advised refugee aid agencies that refugees set to travel before Trump signed his order will now be allowed in. A State Department official said in an email obtained by The Associated Press that the government was "focusing on booking refugee travel" through Feb. 17 and working to have arrivals resume as soon as Monday.

The ACLU and other advocacy groups were urging travelers caught in limbo to act quickly. Omar Jadwat, director of the ACLU’s Immigrants’ Rights Project, applauded the ruling as "another stinging rejection of President Trump’s unconstitutional Muslim ban. We will keep fighting to permanently dismantle this un-American executive order."

Becca Heller, director of the International Refugee Assistance Project, stressed that previously issued visas would once again be valid unless they were stamped "canceled."

"The reinstatement of visas is the only right move to remedy the situation of the last week, which has caused havoc here in the United States and across the world,” Heller said.

Trump had a different take.

"We'll win," Trump told reporters Saturday night. "For the safety of the country, we'll win."