The chaotic roll-out of President Donald Trump's executive order banning travellers and immigrants from seven Muslim-majority countries "is all on me" said the US secretary of Homeland Security on Tuesday (7 February).

"I should have delayed it just a bit so that I could talk to members of Congress," retired General John Kelly told the House Homeland Security Committee. Congress, and "particularly the leadership of committees like this" should have been prepared "for what was coming", he said.

But Fox News has reported that Kelly, along with three top national security officials, including Defense Secretary James Mattis, and Secretary of State Rex Tillerson, told colleagues they were not aware of the details of the executive order until Trump signed it.

Signed on 27 January, the executive order bans people from the predominantly Muslim nations of Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen from entering the US for 90 days and stops refugee applications from these nations for at least four months. The idea behind it is to put a halt on travel and immigration from countries known for terrorism to review how travellers and immigrants are vetted.

The directive's instant enforcement after it was signed at 6pm EST led to protests and confusion at airports throughout the US. It caused travellers around the world to become stranded. A number of people the government says it did not intend to bar were also refused entry to the US, and in some cases deported.

"Lawful permanent residents with green cards were denied. Military advisers who risked their lives to help US forces overseas, as you know, were denied. And students were trapped overseas with visas," said Texas Rep. Michael McCaul, Homeland Security Committee Chair. Kelly, he said, worked quickly to correct "what I consider to be errors".

The order was blocked temporarily on Friday 3 February by a federal court, and its constitutionality may be weighed in the US Supreme Court.

Kelly defended the order and denied reports of people being mistreated by border agents across the US when the ban was implemented. "I've read the reports of people standing up for hours on end — didn't happen. That people were insulted — I guess insults are in the eyes of the beholder," he said.

"We have evidence that citizens of those countries have done terrorist acts in Europe," he said of countries on the banned list. Although none have carried out a terrorist attack in the US. "I believe the vetting on the other end is not adequate," he argued.

"Going forward I certainly would have taken some time to inform the congress," Kelly noted. "That's something that I would certainly do in the future."