"
The president has made no decision to use
force
"
Donald Rumsfeld
US Defense Secretary
A Nato official said the alliance - which includes Iraq's neighbour Turkey - had received proposals for possible roles in any conflict against Baghdad, which the US insists possesses weapons of mass destruction.
But Russia, which does not belong to Nato but does sit on the United Nations Security Council, has warned against an early war, and has sent a senior envoy to Baghdad to seek a diplomatic solution to the crisis.
The Red Crescent aid organisation has already begun preparations in northern Turkey for an expected wave of refugees who would flee if war began.
Suggested roles
The US proposal is reported to follow on from informal discussions with US Deputy Defence Secretary Paul Wolfowitz last month.
Among the suggestions put forward then for possible Nato participation were:
Nato considers an armed attack against a member as an attack against all members, but it is unclear whether it will feel obliged to help the US attack a non-member, Iraq.
US Secretary of Defense Donald Rumsfeld said the request to Nato did not mean that a strike against Baghdad was imminent.
"The president has made no decision to use force, but it does take time to plan, and just as we're planning with individual countries it seemed appropriate, to the extent Nato wished to, to begin that planning process," he told a news briefing in Washington.
'Dangerous consequences'
Russia's Foreign Minister, Igor Ivanov, told the visiting head of the UN's nuclear watchdog, Mohamed ElBaradei, that unilateral military action against Baghdad would have dangerous consequences for world peace.
Mr ElBaradei said Russia could help avert a war but urged Iraq to "shift gear from passive co-operation to active co-operation".
KEY DATES
Chief UN weapons inspector Hans Blix is due to submit his first report to the Security Council on 27 January - a deadline which could be a possible trigger for a US-led war.
His report is to be considered by governments, before the council reconvenes in closed session two days later for a fuller discussion.
BBC News Online's world affairs correspondent, Paul Reynolds, says this might be the key meeting at which positions become clear.
Britain, our correspondent says, might ask the Security Council to give the inspectors more time if nothing significant has changed before then.
British Foreign Secretary Jack Straw is going to Washington for a meeting on Thursday 23 January with the US Secretary of State, Colin Powell.
Prime Minister Tony Blair is expected in the United States to see President George W Bush following the Security Council meetings.
Russian interests
Russia insists that any attack on Iraq must have the backing of the Security Council.
Its high-level delegation to Baghdad is led by a deputy foreign minister, Alexander Saltanov.
Speaking on his arrival, Mr Saltanov said Moscow wanted to find a diplomatic and political solution to the crisis and prevent a war.
The Russian envoy is being accompanied by the country's deputy energy minister, Ivan Matlashov, and representatives of the Russian oil giant, Lukoil.
Analysts say the mission has two aims: firstly to ensure a higher profile for Russian diplomacy, and secondly to secure the country's interests in Iraq.
Russia fears war could hinder its efforts to recover several billion dollars in debt from Baghdad, and jeopardise big oil contracts won by its firms.