The US maintains that Iraq is being obstructive
It will take several months to check whether Iraq has complied fully with its disarmament obligations, chief United Nations weapons inspector Hans Blix says.
"It will not take years, nor weeks, but months," he told the UN
But US Secretary of State Colin Powell responded by saying that Iraq's disarmament efforts had not amounted to the voluntary, active co-operation demanded by UN
By contrast, French Foreign Minister Dominique de Villepin said there was significant evidence of real disarmament.
Iraq was less of a threat to the world than it was before the 1991 Gulf War and there was no need for a US-led assault on the country, he added.
Mr Blix said that Iraq had accelerated its co-operation with weapons inspectors since the end of January as a result of pressure from the international community.
Mohammed ElBaradei, the head of the International Atomic Energy Agency, also submitted a report to the Security Council in which he stated there was no evidence of a revival of Iraq's nuclear weapons programme.
In his report, Mr Blix said inspectors had been able to conduct operations throughout Iraq with relative ease and described the ongoing destruction of al-Samoud II missiles as a "substantial measure of disarmament".
However, he added that such co-operation could not be described as "immediate compliance" - as required by resolution 1441, passed late last year by the Security Council.
Peaceful disarmament is possible and there is a real
alternative to war
German Foreign Minister
He also said there was no evidence to support US claims that Iraq was hiding biological and chemical weapons in mobile laboratories and underground shelters.
But he added that Iraq had failed to provide sufficient documentary information about weapons it claimed to have destroyed, and that interviews with Iraqi scientists appeared to have been subject to "outside pressure".
Mr ElBaradei's report challenged US and British allegations on two key issues.
I still find what I heard this morning a catalogue of
US Secretary of State Colin Powell
Reports that Iraq had tried to purchase uranium from Niger were based on documents that were "not authentic", he said, while extensive examination of imported aluminium tubes suggested that they were not destined for use in enriching uranium.
Mr ElBaradei added that there had been progress on interviewing scientists without minders or tape recorders, but implied that there was still concern that interviews were being bugged.
The inspectors' verdicts were heard by a Security Council split on whether to endorse a new resolution authorising military action.
On the eve of the report, President George W Bush emphatically set out the US agenda for the discussions.
He said the US would call for a new UN vote to pave the way for military action, whatever the level of support in the Security Council - but warned that the US was in the final stages of diplomacy.
Britain, a key US ally, has suggested amendments to a draft text to give Iraq a deadline of a few days before military action is launched. Diplomatic sources told the BBC that the deadline would be 17 March.
The move is intended to win the support of at least nine Security Council votes - including those of the remaining veto-wielding opponents: France, Russia and China.
In other developments:
- US Secretary of State Colin Powell met several foreign ministers ahead of the Security Council meeting, including Russia's Igor Ivanov. Mr Powell discussed changes in the text of the resolution with foreign ministers of major European countries on Thursday
- UN observers say they have found three large gaps in the fence on the Iraq-Kuwait border which may be used in a military advance against Iraq
- Britain's most senior soldier, General Sir Mike Jackson, says his troops are ready to move immediately if the order comes to invade Iraq
- Experts on international law say war against Iraq could be "illegal".