Richard Clarke, who headed a cybersecurity board that gleaned intelligence from the internet, told CBS 60 Minutes in an interview to be aired on Sunday he was surprised administration officials turned immediately towards Iraq instead of al-Qaida and Usama bin Ladin.
"They were talking about Iraq on 9/11. They were talking about it on 9/12," said Clarke.
Clarke said he was briefing President Bush and Secretary of Defence Donald Rumsfeld among other top officials in the aftermath of the devastating attacks.
"Rumsfeld was saying we needed to bomb Iraq. ... We all said, 'but no, no. Al-Qaida is in Afghanistan," recounted Clarke, "and Rumsfeld said, 'There aren't any good targets in Afghanistan and there are lots of good targets in Iraq.'"
Clarke, an adviser to four presidents, left his position in February 2003 after the White House transferred functions of the cybersecurity board to Homeland Security.
Clarke's comments are the latest to raise the question of the Bush administration's focus on overthrowing Iraqi leader Saddam Hussein, one year after the US-led occupation of Iraq.
The administration has struggled to put up any credible evidence to link al-Qaida, blamed for the 911 attacks, with Saddam Hussein's regime.
Former Treasury Secretary Paul O'Neill, fired in a shake-up of Bush's economic team in December 2002, told 60 Minutes in an interview aired in January he never saw any evidence Iraq had weapons of mass destruction - Bush's main justification for going to war.
"They were talking about Iraq on 9/11. They were talking about it on 9/12."
A former White House anti-terrorism adviser
O'Neill also charged that Bush entered office intent on invading Iraq and ousting its leader, Saddam Hussein.
"I think they wanted to believe that there was a connection" between Iraq and al-Qaida, Clarke told 60 Minutes.
"But the CIA was sitting there, the FBI was sitting there, I was sitting there, saying, 'We've looked at this issue for years. For years we've looked and there's just no connection,'" said Clarke.