Ambassadors from the 19 nations were summoned after the three countries formally blocked preparations to defend Turkey, Iraq's Nato neighbour, in the event of a war.

France, Germany and Belgium have argued that preparations for war, even the defence of Turkey, could undermine diplomatic efforts to avert a conflict in Iraq.

Had no member voiced opposition, Nato would have started planning to reinforce Turkey's defences with Awacs surveillance planes, Patriot missiles and special anti-chemical and biological warfare teams.

The move by France, Germany and Belgium is a blow to the United States, which has lobbied hard for more than three weeks for the alliance to start the military planning, backed by 16 of the 19 Nato allies.

Earlier yesterday, Russia joined Germany and France, fellow members of the UN Security Council, in warning the US against a unilateral attack on Iraq.

Speaking after talks in Berlin, Russian President Vladimir Putin, whose country holds veto power on the council, said: "We are convinced that efforts for a peaceful resolution of the situation ... should be persistently continued."

Putin and German Chancellor Gerhard Schroeder both underscored their position that UN inspectors should be given more time to search for any weapons of mass destruction in Iraq.

Schroeder said Iraq "must co-operate fully" with the UN inspectors. But he and Putin insisted that could be achieved without war.

They also said China was broadly in agreement.

"We see no basis for the use of force at this time," Putin said, adding that the next steps should be considered at the UN after chief weapons inspector Hans Blix presents a new report on Iraqi co-operation on Friday.

Schroeder and Putin sidestepped questions about a German-French initiative to bolster weapons inspections, reportedly including a proposal to send thousands of UN soldiers to effectively sideline Iraq President Saddam Hussein and give muscle to a sharply stepped-up number of inspectors.

US officials have sharply criticised the idea, saying it diverts from the purpose of making Saddam disarm.

Putin has now gone to Paris for talks with French President Jacques Chirac.

Blix and his fellow UN inspector Mohamed ElBaradei left Iraq yesterday with more Iraqi documents in hand, and new ideas for tracking old weapons.

They said they sensed a "good beginning" and a changed "positive attitude" in Baghdad towards their job of ensuring Iraq is free of banned arms.

But in their two days of talks, the inspectors did not win immediate agreement, as expected, for U-2 reconnaissance flights over Iraq.

The Iraqis handed over more documents to try to clarify lingering questions about 1980s chemical and biological weapons, and said they would establish commissions to search for additional documents and any leftover weapons.

"I'm beginning to see some positive attitude," Blix said.

ElBaradei added: "We are leaving with a sense of cautious optimism. We see a very good beginning, and would like to see much more in the coming weeks."

However, in Washington, President George W. Bush, in another heavy hint of imminent war, said again that Iraq's "game" of concealment was over.

The US and British Governments contend that Iraq retains chemical, biological and nuclear weapons programmes prohibited by UN resolutions, and threaten a military strike against it if, in the US view, it has not disarmed sufficiently.

As tens of thousands of American military personnel train in the Gulf region for possible war, Bush told US congressional Republicans at a policy conference that Saddam "wants the world to think that hide-and-seek is a game that we should play. And it's over".

Bush said it was a "moment of truth for the United Nations".

The Security Council banned Iraqi weapons of mass destruction and longer-range missiles after Iraq was defeated in the 1991 Gulf War following its invasion of Kuwait.

During the 1990s, UN inspectors oversaw the destruction of the great bulk of chemical and biological weapons, and dismantled Iraq's programme to build nuclear bombs.

The UN experts resumed inspections last November, after a four-year gap, to certify that Iraq has no leftover weapons and did not restart the arms programmes during the UN absence.

Blix complained in a Security Council report last month that the Iraqis were not co-operating on "substance" - by supplying evidence to clear up remaining questions about VX nerve agent, anthrax and some other doomsday weapons developed in the 1980s.

Blix and ElBaradei have now reported receiving documents - the Iraqis said there were 24 - offering "explanations", if not hard evidence, regarding outstanding issues on anthrax, VX and Iraqi missile development.

Blix said the documents would have to be studied by his experts to determine their value.

In other developments yesterday:

* Iraqi Foreign Minister Naji Sabri visited Iran in a surprise diplomatic move. Tehran, a leading opponent of Saddam's regime, has rejected unilateral military intervention.

* The Pope ordered that a special envoy be sent to Iraq to emphasise his plea for peace and encourage Iraqi authorities to co-operate with the UN.

* US Defence Secretary Donald Rumsfeld said he would prefer to see Saddam flee Iraq than for the West to go to war.

Rumsfeld said "plenty" of countries would take in the dictator and promise not to extradite him.

* Former South African President Nelson Mandela has been asked to negotiate an exit plan for Saddam in efforts to avert a war.

The Nobel Prize laureate was asked by "distinguished people", including leaders of Arab states bordering Iraq, to persuade Saddam to step down.

Mandela's spokeswoman, Zelda la Grange, said he would intervene only at the UN's request.

* China will evacuate non-essential staff from its embassy in Baghdad because of the deepening tensions.

* Australian Prime Minister John Howard said it was time for Saddam to get "fair dinkum" about disarmament if he is to avoid war.

Howard will meet Bush at the White House today.