The latest twist in the months-long legal battle, which has dealt a stinging setback to Trump's young administration.
The latest twist in the months-long legal battle, which has dealt a stinging setback to Trump's young administration, took place in the western city of Seattle where a crowd rallied in protest at the contested immigration ban.
Three judges from the US 9th Circuit Court of Appeals were considering Trump's challenge of a judge's order blocking his ban on refugees and nationals from six Muslim-majority countries.
A Hawaii-based judge in March issued a preliminary injunction -- which applies nationwide -- against the order on grounds it was motivated by anti-Muslim bias.
The Trump administration says the temporary ban, which concerns travelers from Iran, Syria, Sudan, Libya, Somalia and Yemen, is motivated by national security concerns.
The government's lawyer Jeffrey Wall also reiterated on Monday that Trump's rhetoric against Muslims during the election campaign should not be taken into account by the judges who appeared sceptical.
Wall said that Trump had clarified over time that "what he was talking about was Islamic terrorist groups and the countries that sponsor or shelter them."
He also argued that the ban was not based on religion and that those challenging it -- the state of Hawaii and an imam -- have no standing in the case.
However Neal Katyal, the attorney representing Hawaii, dismissed those arguments telling the judges that Trump clearly was singling out Muslims and that his campaign rhetoric was still relevant today.
"We have not seen anything like this in our lifetime in which a president is establishing a disfavored religion," Katyal said.
He said Congress had set rules on vetting foreigners before they enter the United States and Trump could not claim sweeping powers and take a "magic eraser" to long-standing policies.
Monday's hearing came a week after a federal court in Maryland also heard arguments on whether to uphold a separate judge's decision blocking the ban.
The scope of Trump's revamped ban, signed in early March, was reduced from his original January effort, which blocked travelers from seven-majority Muslim countries, including Iraq, as well as all refugees.
The first decree -- which prompted mass protests and sowed chaos at US airports -- was blocked on grounds it violated a ban on religious discrimination, a ruling upheld on appeal.
The modified version removed Iraq from the ban, but ran into the same objections.