The Ninth Circuit Court of Appeals has asked for both sides to file legal briefs before the court makes its final decision after a federal judge halted the program on Friday.
What this means is that the ruling by US District Court Judge James Robart, who suspended the ban, will remain in place -- for now.
The US Justice Department filed an appeal just after midnight Sunday, asking to pause Robart's sweeping decision that temporarily halted enforcement of several key provisions of Trump's executive order.
The order bars citizens of seven Muslim-majority countries -- Iraq, Syria, Iran, Libya, Somalia, Sudan and Yemen -- from entering the US for 90 days, all refugees for 120 days and indefinitely halts refugees from Syria.
The Justice Department's strongly worded court filing lodged a multi-pronged attack on Robart's decision, emphasizing that halting enforcement of the travel ban "harms the public" and "second-guesses the President's national security judgment" in the immigration context.
"(Robart's ruling) contravenes the considered judgment of Congress that the President should have the unreviewable authority to suspend the admission of any class of aliens," the Justice Department wrote in its filing.
"Courts are particularly ill-equipped to second-guess the President's prospective judgment about future risks. Unlike the President, courts do not have access to classified information about the threat posed by terrorist organizations operating in particular nations, the efforts of those organizations to infiltrate the United States, or gaps in the vetting process," the filing said.
Justice Department lawyers further argued that the parties who filed the lawsuit -- the attorneys general of Washington state and Minnesota -- lack the ability to sue in federal court because their alleged harms are too "speculative."
Since the federal appeals court rejected a request to immediately reinstate the travel ban, lawyers for Washington state and Minnesota have until 3:59 a.m. ET Monday to file legal papers, and the Justice Department lawyers have until 6 p.m. ET Monday evening to reply.
The 9th Circuit extended the filing deadline for one hour because of computer system maintenance.
Then a three-judge panel will decide whether to schedule a hearing or issue a ruling.
Robart, a Bush appointee sitting in the Western District of Washington, ruled Friday that the states that filed the lawsuit "have met their burden of demonstrating that they face immediate and irreparable injury as a result of the signing and implementation of the executive order."
Robart explained that Trump's executive order adversely affects "residents in areas of employment, education, business, family relations, and freedom to travel."
When Trump was asked at a gala in Florida on Saturday whether he was confident his administration would prevail in the appeal, he replied, "We'll win. For the safety of the country, we'll win."
On Saturday, the Department of Homeland Security announced it had suspended "any and all" actions to implement the immigration order and would resume standard inspections of travelers, as it did prior to the signing of the travel ban.
After the Ninth Circuit's decision on Sunday, a US Embassy official in Baghdad said that holders of valid US visas, including Iraqi Special Immigrant Visas, would be allowed to travel to the United States.
"The US Government has determined that it is in the national interest to allow Iraqi Special Immigrant Visa (SIV) holders to continue to travel to the United States," the embassy official said, adding that the embassy had been in contact with the SIV applicants.