US poised to launch 'rolling attack' as reinforcements continue to arrive

British and American troops massing on the Iraqi border moved into forward positions yesterday in readiness for a military strike that could start as soon as tonight.

Some soldiers were up before dawn, taking down tents and packing essential kit for the push north. Robert Vennebush, 25, an enthusiastic sergeant with a US army engineering unit, said: "Finally we're going somewhere. We're going to war."

In another camp, soldiers from the US First Marine Division, which will lead the drive toward Baghdad, began loading their gear on to Humvees to pull out.

The first phase of the strike is likely to be a massive volley of cruise missiles and aimed bombs – up to 3,000 in all – designed to destroy defences and to stun Iraqi forces into submission. America intends to pursue a co-ordinated "rolling strike" against Iraq, making use of the troops it has in the region even as others arrive.

CNN quoted US officials last night as saying that America might launch a small military action even before the 48-hour deadline to Saddam Hussein expires.

Lieutenant-General William Wallace, the US army commander, said: "We recognised from the very beginning that we're going to be fighting and building up combat power at about the same time."

This strategy is close to what was initially envisaged by Donald Rumsfeld, the US Defence Secretary, who was keen to use highly mobile airborne troops to launch the strike – albeit supported by massive air power – rather than a more traditional, heavily armoured force, as would have been preferred by the head of US Central Command, General Tommy Franks. Everyone agrees that air power is the key to this operation because it allows America and Britain to launch the attack with a much smaller ground force than they would otherwise need.

Britain is providing about 10 per cent of the air power – some 100 aircraft in all – which is controlled from the Joint Force Air Command headquarters at Prince Sultan air base in Saudi Arabia. The overall air commander is an American air force general, while his second in command is British, Air Vice-Marshal Glenn Torpy.

A senior RAF officer, who asked not to be named, said up to 2,000 targets had been identified inside Iraq. Among the targets to be struck in the opening attack – in which he said the RAF would be involved – would be the communications facilities with which President Saddam could control any weapons of mass destruction he might or might not have. The RAF officer admitted that despite intense planning and the use of weapons that are far more accurate than they were a decade ago, there were still certain to be civilian casualties.

"We have no wish to lay waste to Iraq," he said. "We will do what is required to get people in and occupy the place and get those weapons of mass destruction. But there will be mistakes. There are mistakes in any war. I don't want you to go away thinking that we can do this without hurting someone. We cannot."

The rolling strategy that will back up the air strikes has been forced upon America, partly because of the delay in obtaining Turkey's permission for 62,000 US troops and their armour to open a northern front from their soil and partly because of an apparent failure to deploy troops quickly enough. Even now, three powerful US armoured units are still in America or Europe and will not be in the Gulf region until mid to late April. The only heavy unit to have arrived in Kuwait is the 3rd Infantry.

Indeed, the force strength regularly quoted by the Pentagon is somewhat misleading. While it says that about 225,000 US forces are in the region, about half of this number is made up of naval and air force personnel. The actual number of soldiers and marines is close to 120,000, supported by about 26,000 British troops.

Analysts say that the Pentagon failed to deploy forces quickly – the 1st Armoured Division and the 1st Cavalry were not given orders to leave for the Gulf until 4 March.

All of this means two things for America and Britain – the reliance on its air power and the importance of the first 48 hours of the operation. The opening strikes will be crucial.

In these circumstances the taking of the southern city of Basra – a task given to the British forces – has become increasingly important. British forces hope that the largely Shia population of the city will welcome them. The Washington Post reported that the military would fly in journalists to film any scenes of jubilation once British and American forces arrived. A US Marine spokesman, Chris Hughes, said: "The first image of this war will define the conflict."

¿ The White House said last night that US forces would enter Iraq to search for weapons of mass destruction even if President Saddam complied with the deadline to leave.