A former top Iraqi official has said that Saddam Hussein survived the Gulf War along with his two sons, US defence sources say.
The fate of Saddam and his sons is a headache for the US
Mahmud al-Tikriti told interrogators that he had spent time in hiding with Uday and Qusay Hussein and their father after the end of the war this spring.
Mr Tikriti said that he and the two sons had sought refuge in Syria and had not seen Saddam since they left. They were later allegedly expelled by the authorities in Damascus.
America's administrator in Iraq, Paul Bremer, said the US had reached no conclusion as to whether Saddam was alive or dead.
"I think it's important for us to try to reach a conclusion and to be able to show why we reached that conclusion - have him captured and show him alive, or prove definitively that he is dead," he said at the World Economic Forum in Jordan.
We know that this guy was Saddam's shadow at one time, but who knows what's true and what's not
on Mahmud al-Tikriti
A British newspaper reported on Sunday that that US had fired missiles at a convoy believed to be carrying Saddam Hussein and at least one of his sons.
The Observer said the US was carrying out DNA tests to see if the former president was killed in the missile strike on Wednesday.
The paper said US forces had launched their attack based on an intercepted phone call.
There has been no confirmation of the Observer report.
The BBC's Chris Morris reports from Saddam's home town, Tikrit, that loyalty to the deposed dictator is still strong there with many people saying they would willingly help him evade capture.
US officials caution that the accuracy of the information given by Mr Tikriti has not been fully assessed since his capture in Iraq on Monday.
But recent US intelligence intercepts suggest Saddam Hussein and his sons are alive and in Iraq, and efforts to capture them have intensified.
Mahmud al-Tikriti is the most senior official to be captured
Mahmud al-Tikriti - the "ace of diamonds" in the US pack of cards of top wanted Iraqis - ranked only behind Saddam and his sons in the Iraqi leadership.
He has been questioned over the last four days by US officials in Baghdad.
"We know that this guy [Mr Tikriti] was his [Saddam's] shadow at one time," an unnamed US official told Reuters news agency on Saturday.
"But who knows what's true and what's not
A defence official who spoke to the New York Times said one had to be careful about the information being given by Mr Tikriti because "for many, many years... [he] was part of the lies and deception".
Mahmud al-Tikriti was one of Saddam Hussein's closest aides, frequently at his side and controlling access to the former Iraqi president.
In the weeks after the war, US Defence Secretary Donald Rumsfeld said that some senior Iraqi officials had fled to Syria, and called on Damascus to hand them over.
Syria has strongly denied harbouring Iraqi fugitives.
In Tikrit, Chris Morris reports, there is a big American military presence and local commanders are confident that they are getting closer to their most important target.
The trouble is they face massive hostility from a population which was always loyal to Saddam Hussein - the local boy made good.
In the house on the outskirts of Tikrit where Mr Tikriti was found, our correspondent reports, people say they would offer the former president refuge as well if he turned up on their doorstep.
On the town's dusty main street, freshly painted graffiti in Arabic curses George W Bush and says Saddam is a hero.