Saddam Hussein did not order a counter-attack against invading US troops because he thought it was a ruse, the Washington Post reports.
Saddam failed to believe mounting evidence of a US attack, reports say
The Iraqi leader had been convinced by French and Russian contacts that there would be no US land invasion.
Ex-Iraqi Deputy Prime Minister Tariq Aziz made the claims under questioning, the Post said, citing US interrogators.
US officials say Mr Aziz, once the international face of the Iraqi regime, is not a reliable witness.
Nevertheless, the Washington Post notes his co-operation with his questioners is important as the US-led coalition tries to understand Saddam Hussein's behaviour.
After meeting Russian and French intermediaries Saddam Hussein was convinced he could avoid a war, Mr Aziz reportedly told interrogators.
They assured the Iraqi president that they would block a US-led war through delays and vetoes at the United Nations Security Council, according to Mr Aziz's reported statements.
The French and Russians then convinced Saddam Hussein that Washington would wage a long air war first as it had done in previous conflicts, Mr Aziz is said to have told questioners.
The Washington Post says Mr Aziz's reported comments convey Saddam Hussein on the eve of war as "a distracted, distrustful despot, who was confused, among other things, by his meetings with Russian and French intermediaries".
He believed he might avoid a war and buy enough time for a ceasefire to be brokered by Paris and Moscow.
So despite mounting evidence to the contrary, and even as American forces poured into Iraq, Saddam Hussein refused to order an immediate military response, believing the land invasion was some kind of trick.
US officials involved in questioning Mr Aziz, who surrendered to US forces in April, say that his accounts have not been corroborated by other sources, the Post reports.
They are wary of his claims because Mr Aziz had grown apart from Saddam Hussein as war approached.
The officials also point to what is termed "his history of deceit and opportunism" and believe that he might be trying to pander to his American captors' anger at French and Russian conduct before the war.
However, his comments form part of information being gathered by US officials as they try to understand why Saddam Hussein behaved as he did if he had no weapons of mass destruction.
Several high-ranking detainees have said they believe the Iraqi leader was afraid to lose face with his Arab neighbours who respected him precisely because they feared he had such an arsenal, the Post reports