The UN's atomic watchdog says it is confident there is not enough radioactive material missing in Iraq to make a nuclear "dirty bomb".
Troops have not unearthed any Iraqi weapons of mass destruction
Vilmos Cserveny, a spokesman for the International Atomic Energy Agency, said: "We don't have concerns about any missing uranium" in Iraq.
Earlier, the US revealed that it had secretly removed more than 1.7 metric tons of radioactive material from Iraq.
Some nuclear material remains in Iraq under IAEA control, Mr Cserveny said.
"The remaining sources are not suitable for malevolent purposes," he told BBC News Online.
US Energy Secretary Spencer Abraham said on Tuesday that the US had removed 1.77 tons of enriched uranium and about 1,000 "highly radioactive sources" from Iraq's former nuclear research facility at al-Tuwaitha on 23 June.
The IAEA and Iraqi officials were informed ahead of the operation, which happened before the 28 June handover of sovereignty.
'Dirty bomb' fears
The threat of a terrorist "dirty bomb" explosion in a city is a major concern of Western intelligence agencies, correspondents say.
Rather than causing a nuclear explosion, a "dirty bomb" would see radioactive material combined with a conventional explosive - probably causing widespread panic and requiring a large clean-up operation.
Al-Tuwaitha was Iraq's biggest nuclear complex
In June last year, the IAEA said it had accounted for most of the uranium feared stolen from the al-Tuwaitha site, south-east of Baghdad.
A statement from the US energy department (DOE) on Tuesday said 20 of its laboratory experts had repackaged "less sensitive" nuclear materials that would remain in Iraq.
Such materials could be used for medical, agricultural or industrial purposes, it said.
Al-Tuwaitha - dismantled in the early 1990s under UN ceasefire resolutions - played a key role in Iraq's drive to build nuclear weapons prior to the 1991 Gulf war.
The 1,000 "sources" evacuated in the Iraqi operation included a "huge range" of radioactive items used for medical and industrial purposes, a spokesman for the US National Nuclear Security Administration told AP news agency.
Bryan Wilkes said much of the material was "in powdered form, which is easily dispersed".
It was flown out of the country aboard a military plane in a joint operation with the Department of Defense, and is being stored temporarily at a DOE facility.