British and US intelligence sources have been giving conflicting opinions on the success of an air strike designed to kill Saddam Hussein.
The raid was carried out within 45 minutes of a tip-off
US sources say they saw him entering the building in Baghdad on Monday and that he did not emerge before four satellite-guided US bombs destroyed it.
But Britain's intelligence agency, MI6, has reportedly told the CIA that the Iraqi leader left the building moments before the strike in the Mansour district.
Military commanders warn that it may take some time to establish if Saddam Hussein was, indeed, killed.
Success may depend on whether the US has a sample of his DNA.
However, a former chief of protocol for Saddam Hussein told the BBC he believed the Iraqi leader was not even in Baghdad at the time of the strike.
The Washington Post on Wednesday cited US government officials as saying that multiple eyewitness accounts were suggesting the Iraqi leader had been killed.
Saddam would never use any place visited by him or his family before
Former Iraqi chief of protocol
One of the officials described the CIA as being "in a state of euphoria", it said.
"They say there is no doubt he is dead," the paper quoted a US military official as saying.
However, the US Government line is to caution that no firm conclusion has yet been reached.
An intelligence official told the Post there was no doubt senior Baath Party and intelligence officials had been killed, but their identity could not be known.
Has Saddam Hussein already left Baghdad for his hometown Tikrit?
The Washington Times reported that Saddam Hussein had been tracked by the CIA, a CIA-recruited spy and a Delta Force commando.
The CIA had stepped up surveillance after a videotape, allegedly of Saddam Hussein walking in Mansour, was broadcast on television last Friday.
Some reports say 30 people were believed to have been meeting on Monday in a bunker behind or underneath the al-Saa restaurant in Mansour.
In and around Tikrit he could depend upon a more sustained resistance
However, Haitham Rashid Wihaib, an Iraqi defector who was for many years Saddam Hussein's chief of protocol, said the Iraqi leader would never visit the same place twice.
"He rented 5,000 ordinary Iraqi houses in poor areas... so that he can move from one place to another," he said.
"He left Baghdad the moment he felt the American and British troops were approaching. He left for Tikrit."
Mr Wihaib said Saddam Hussein would be looked after by his people in his hometown, would try to keep a low profile and hope for his doubles to save him.
Charles Tripp, a Middle East analyst from the School of Oriental and African Studies in London, agrees there is a good chance he may have tried to leave the capital.
"I think he would probably feel that in and around Tikrit he could depend upon a more sustained resistance."
Monday's bombing left an 18 metre-deep crater, broke windows and doors up to 300 metres away.
Eyewitnesses said two houses were flattened and nine Iraqis were killed.
It was the second "decapitation" strike aimed at the Iraqi leadership.
On the first night of the war, 19 March, an air strike on a Baghdad compound tried to kill Saddam Hussein, but US intelligence sources believe he survived.