George W. Bush first mentioned a link between Saddam Hussein and Al-Qaeda to Tony Blair days after 9/11, but the premier advised against pursuing the Iraqi dictator, an aide said Monday.

The then US president spoke to Blair in a telephone conversation on September 14, 2001 and mentioned the possible Iraq link, said David Manning, who was Blair's foreign policy adviser at the time.

In the conversation Bush "said that he thought there might be evidence that there was some connection between Saddam Hussein and Osama bin Laden and Al-Qaeda," Manning told Britain's Iraq war inquiry, which started last week.

"The prime minister's response to this was that the evidence would have to be very compelling indeed to justify taking any action against Iraq," he added.

The inquiry, Britain's third related to the conflict, is looking at its role in Iraq between 2001 and 2009, when its operations ended, and is to report its findings by the end of 2010.

In its first week the probe heard that Britain's ambassador to the United Nations at the time, Jeremy Greenstock, believed the invasion to be "of questionable legitimacy".