They were the seven minutes that, for some, came to define a presidency. On one side of the TV screen, a New York landmark was in flames after hijacked planes smashed into the World Trade Centre. On the other, George Bush sat before a group of children looking like a startled rabbit, conveying a sense of paralysis, if not panic, after an aide told him of the attacks.

But Bush says that anyone who thinks he was in shock has got it wrong. He was trying not to create panic. "My first reaction was anger. How dare they do this to America?" Bush told NBC News in an interview to be broadcast on Monday to coincide with the release of his memoirs.

"I made the decision not to jump up and create a chaotic scene, because right after … These are quick reflections, anger, duty to protect the country, and then all of a sudden the cellphones are ringing. Now, the noise [from reporters receiving calls about the attacks]," he said. "But it clarified to me that people were going to be watching my reaction. And I'd had enough experience as governor of Texas during some disasters to know that the reaction of the leader is essential in the first stage of any crisis."

Pressed on whether he was paralysed into inaction, Bush was dismissive. "I'm not going to debate the critics as to whether or not I was in shock or not. I wasn't. And they can read the book, and they can draw their own conclusion," he said.

Bush's book, Decision Points, offers insights into his beliefs, including a vigorous defence of the death penalty in an argument over dinner with Cherie Blair.

Much of it is dedicated to justifying what some consider to be indefensible, not least his invasion of Iraq on what proved to be the spurious pretext of hunting for weapons of mass destruction. The former president acknowledges there were dissenters on the question of whether to go to war. He claims he was among them.

"I was a dissenting voice. I didn't want to use force. I mean force is the last option for a president," he said.

But he told NBC there was no need for an apology. "I mean apologising would basically say the decision was a wrong decision. And I don't believe it was the wrong decision," he said.

The memoirs give a glimpse of the paranoia that engulfed his administration in the weeks after the 9/11 attacks. Bush relates how later that year he was visiting China when his vice-president, Dick Cheney, came on the secure video link and said: "Mr President, we have a problem."

Before talking they needed to make sure the Chinese weren't listening, and they assumed that the president's hotel suite was bugged. "Condi [Rice], Andy Card, Colin Powell and I are sitting in a cramped tent in a Chinese hotel. The reason we're in the tent is because Chinese listeners cannot penetrate the tent," wrote Bush.

Cheney revealed that a botulism detector at the White House had gone off and Bush might be contaminated. "We had all been exposed to it … and had we inhaled it we could easily be dead," he said. Tests on mice would tell. Bush wrote: "We kind of chuckled and said: Well, if the mice are feet up, we're goners. And if they're feet down, we're fine."