WASHINGTON - Secretary of Homeland Security John Kelly acknowledged to lawmakers on Tuesday (Feb 7) that President Donald Trump's travel ban from seven Muslim-majority countries had been rushed and would have benefited from better coordination.

But he defended the ban, saying he expected the administration to win a court challenge.

"I should have delayed it just a bit so that I could talk to members of Congress, particularly to the leadership of committees like this, to prepare them for what was coming," Gen Kelly told the House Committee on Homeland Security.

He supported, however, Mr Trump's contention that it was not a Muslim ban and defended the order as "lawful and constitutional" and said the review ordered by the president was "necessary and appropriate".

As the 9th US Circuit Court of Appeals in San Francisco heard arguments on Tuesday over whether to lift a stay on enforcement of the ban, immigration lawyers and refugee groups continued to try to take advantage of the window provided by a federal judge in Seattle to bring refugees into the country.

"While some of the core tenets of this order are the subject of ongoing litigation, it is my belief that we will prevail and be able to take the steps necessary to protect our nation," Gen Kelly said.

"Americans must feel safe to walk down the street, go to the mall or to a nightclub anywhere and anytime. Fear must not become the status quo as it has in so many parts of the world."

In the meantime, a complaint filed with the inspector general for homeland security details what two legal advocacy groups call "systemic abuses and violations of the rights of individuals lawfully entering the United States" after the executive order banning travel from the seven countries was issued.

People caught up in the confusion after the ban was imposed were denied access to lawyers, held in detention for hours without food, and in some instances coerced into signing away their entry visas, the Kathryn O. Greenberg Immigration Justice Clinic at Cardozo Law School and the Center for Constitutional Rights said in a complaint filed late Monday.

The complaint was redacted to protect the names of people caught up in the disruption. It included 26 accounts by lawyers barred from reaching their clients and in some cases by affected individuals or their relatives.

In his testimony, Mr Kelly rejected accusations that inspectors had insulted or mistreated those caught up in the confusion after the order was signed by Mr Trump.

"Everyone was treated humanely," said Gen Kelly, a retired Marine Corps general recently confirmed as homeland security secretary. "We did have to step back and kind of re-cock in that first 24-hour period because of action by one of the federal courts. That changed things a bit, so we had to kind of step back."

He said he also agreed with a Twitter post by Mr Trump that dangerous people could be getting into the country while a court order has held up the ban. He said it was "entirely possible" and it was likely that law enforcement officials would not know "until the boom".

Mr Michael McCaul, chairman of the Homeland Security Committee, said the roll-out of the executive order had been problematic. The Republican said he was concerned about "the lack of coordination, both within the executive branch and also with congressional leaders like myself".

But he said he applauded Gen Kelly for "quickly correcting what I consider to be errors by quickly granting the exception and waiver to green-card holders, which went a long way to remedy, I think, this executive order".

Gen Kelly said most of the confusion occurred because of the multiple court rulings issued in response to the order and the many protesters who appeared at airports across the country, not because of the actions of Customs and Border Protection officers.

Mr Bennie G. Thompson of Mississippi, the ranking Democrat on the committee, said he agreed that there had been problems with the roll-out of the travel ban. However, he rejected Gen Kelly's testimony that the order had not caused chaos at the airports, as customs officers tried to determine who would be denied entry.

"They were put in an untenable position. Basically, they were flying by the seat of their pants trying to interpret an EO that had no directives to go with it," Mr Thompson said, referring to the executive order.

"You had LA doing one thing, Atlanta doing one thing and JFK doing another. So I'm troubled by the comment that he made that there was no chaos."

Mr Thompson said he and other members of Congress had requested copies of the guidance that US Customs and Border Protection sent to its officers after the immigration order was signed but had not received the information so far.

"Our feeling is that the normal vetting that goes with the issuance of an EO was not done," he said.