Huge convoys have moved across the Kuwaiti desert ahead of President George W Bush's 0100 GMT Thursday ultimatum for Saddam Hussein to leave Iraq or face military conflict.

The BBC's Nick Childs says that US aircraft have attacked Iraqi surface-to-surface missile and artillery installations in the western and southern Iraq, but the Pentagon insists that this is still in support of the no-fly zones and it is not the start of the war proper.

Officials at US military headquarters in Qatar have told the BBC that no action will be taken before the deadline has passed, unless the Iraqi forces attack first.


- ATTACK OPTIONS

An air force colonel briefing reporters at the Pentagon said that the opening hours of the war would be devastating and that he did not believe the potential adversary had any idea what was coming.

With battle looming the UN Secretary General Kofi Annan said his thoughts were with the ordinary people of Iraq as they faced the "disaster of war".

He warned the US and UK that "under international law, the responsibility for protecting civilians in conflict falls on the belligerents".

The BBC's Paul Wood in the Iraqi capital says that the streets of Baghdad are now eerily empty as residents hide in fortified rooms in their houses or in public shelters beneath large buildings.

The only people outside are the armed traffic police and those manning the machine guns atop trucks or the sandbagged bunkers on street corners.

The majority of the city's five million residents remain, unable to afford the $1,000 being charged on Wednesday for a seat in taxi to flee to safer areas.

With their stockpiles of food around them they sit and wait with their families, our correspondent says.

In other developments:

- Mr Bush sends formal notification of his justification for military action to the US Congress

- UK Prime Minister Tony Blair holds a 20-minute phone call with Mr Bush

- The people of Baghdad are preparing to defend their city

- Germany expels four Iraqi diplomats for activities considered "incompatible with their diplomatic status"

- Seventeen Iraqi soldiers surrender to American forces on the Kuwaiti border

- Iraqi Deputy Prime Minister Tariq Aziz appears on state television to refute rumours that he has fled the country or been killed

- The Turkish Government is asking parliament to allow US planes to use its air space, with a vote expected on Thursday

- Aircraft drop nearly two million leaflets on south-eastern Iraq, urging Iraqi troops to lay down their arms.

- Shock tactics

Once the US deadline expires there will only be a limited period of darkness available for what could be a simultaneous air and ground attack.

But the BBC's Jonathan Marcus in Qatar says General Tommy Franks, the overall US commander, could determine that the shock of the initial onslaught will be sufficient to allow his forces to advance even in daylight.


- US aims for swift war

The city of Basra and the oilfields of southern Iraq will be among the first objectives.

The Pentagon has denied a report from Kuwaiti security sources that US troops had passed into the demilitarised zone that straddles the Kuwait-Iraq border.

The White House has said it hopes the war with Iraq will be swift, but has warned the American public to "be prepared for loss of life".

"Americans ought to be prepared for the importance of disarming Saddam Hussein to protect the peace," President Bush's spokesman Ari Fleischer said.

Earlier, Iraqi Information Minister Mohammed Saeed al-Sahhaf said Washington was lying to US troops about the number of casualties they could expect.

"To say that invading Iraq will be like a picnic is a stupid idea... they are [sending them to] definite death," he warned.