Former Treasury Secretary Paul O'Neill contends the United States began laying the groundwork for an invasion of Iraq just days after President Bush took office in January 2001 - more than two years before the start of the U.S.-led war that ousted Saddam Hussein.

``From the very beginning, there was a conviction that Saddam Hussein was a bad person and that he needed to go,'' O'Neill told CBS's ``60 Minutes'' in an interview to be aired Sunday night.

The official American government stance on Iraq, dating to the Clinton administration, was that the United States sought to oust Saddam.

But O'Neill, who was fired by Bush in December 2002, said he had qualms about he asserted was the pre-emptive nature of the war planning.

``For me, the notion of pre-emption, that the U.S. has the unilateral right to do whatever we decide to do, is a really huge leap,'' according to an excerpt of the interview that CBS released Saturday.

The administration has not found evidence that the Iraqi leader was involved in the Sept. 11 attacks but officials have said they had to consider the possibility that Saddam could have undertaken an even larger scale-strike against the United States.

White House spokesman Scott McClellan would not confirm or deny that the White House began Iraq war planning early in Bush's term. But, he said, Saddam ``was a threat to peace and stability before September 11th, and even more of a threat after September 11.''