The US-led team hunting for weapons of mass destruction in Iraq has not found any stockpiles of biological or chemical weapons, but will keep searching the country, according to CIA adviser Mr David Kay.
He presented his findings in a classified interim report to US lawmakers today.
"We have not yet found stocks of weapons, but we are not yet at the point where we can say definitively either that such weapon stocks do not exist or that they existed before the war and our only task is to find where they have gone," Mr Kay said in a statement.
The team has also not found any evidence to confirm pre-war reports that the Iraqi military was prepared to use chemical warfare against US-led forces.
The United States went to war against Iraq in March and ousted Saddam Hussein from power in April, largely on the premise Baghdad posed a threat through the development of unconventional weapons of mass destruction.
But no such weapons have yet been found, and critics have questioned whether the Bush administration exaggerated the threat to get support for the war.
Much evidence has been "irretrievably lost," Mr Kay said. "It is far too early to reach any definitive conclusions and in some areas, we may never reach that goal," he continued.
"Despite evidence of Saddam's continued ambition to acquire nuclear weapons, to date we have not uncovered evidence that Iraq undertook significant post-1998 steps to actually build nuclear weapons or produce fissile material," he said.
"However, Iraq did take steps to preserve some technological capability from the pre-1991 nuclear weapons program," he added.