The report, which was delivered to the UN secretary general, Kofi Annan, on Wednesday, and formally circulated yesterday evening, remained critical of the extent of Iraqi cooperation but noted that significant progress had been been made.

"Iraq could have made greater efforts to find any remaining proscribed items or provide credible evidence showing the absence of such items," Mr Blix wrote in his 17-page report. "The results in terms of disarmament have been very limited so far."

"It looks like a straight report," one British official said. "But it shows that none of the unanswered questions have been answered, and no substantive developments."

The report has emerged at a time when the security council appears more divided than ever. After informal discussions in the council yesterday, both factions were claiming that the majority support of members was either with them or moving in their direction.

The Russians suggested that their country did not need to consider using its veto, as opposition to the use of force was great enough to defeat the new British and American resolution without such an "extreme measure". But Moscow implied that it would be prepared to use the power if necessary.

In a further sign of a deepening divide, Moscow yesterday condemned the US for putting "moral and psychological pressure on the inspectors". In an interview with the Guardian, Alexander Yakovenko, chief spokesman for the Kremlin's foreign minister, Igor Ivanov, said it was clear "there are concrete forces within Washington that are dissatisfied that the inspectors cannot present some sort of evidence of a violation by Iraq of security council resolutions".

Mr Yakovenko was confident that the Franco-German-Russian memorandum would see off any resolution attempting to pave the way for the use of force.

Over the past month Mr Blix's reports have strengthened the hand of one side or the other: first the hawks on January 27, and then the doves on February 14. But this latest statement can be interpreted either way. "It is a mixed bag," one diplomat said.

None the less, Mr Blix did imply Iraq had been showing greater willingness to cooperate than in the past.