While the American forces press northwards towards Baghdad, British troops in southern Iraq are continuing to encounter resistance.
Two British soldiers are missing in southern Iraq.
All units are reporting "niggly" sniping attacks from "Saddam Hussein zealots and militia using guns and rocket-propelled grenades" according to British army headquarters, said BBC correspondent Tim Franks on the Iraqi border.
But BBC correspondent Paul Adams, in Qatar, said some reports had been misleading because they focused on specific episodes which were almost irrelevant at the strategic level.
"You have to keep your eye on the big picture, and the big picture is one of extraordinarly rapid progress," he said.
This was the message also of US military commander, General Tommy Franks, who said coalition forces were making "rapid and, at times, dramatic progress", and described the Iraqi resistance as "sporadic".
And Group Captain Al Lockwood, British forces spokesman in the Gulf, said: "The campaign is going very much according to the schedule and the plan that has been set.
"These pockets of resistance that we're encountering tend to be what we're calling irregular troops - members of Saddam Hussein's regime".
But he warned that if they continued to resist they would be "dealt with".
Meanwhile there have been reports that four suicide squads have been deployed to southern Iraq to target British marines, according to intelligence given to 3 Commando Brigade.
It is thought captured prisoners of war warned Iraqi bombers could strike at a commando patrol or base using an ambulance packed with explosives.
All commandos have been ordered to wear body armour vests and helmets at all times when outdoors, even in areas that have been secured.
It is believed the bombers are likely to be members of the Fedayeen - a paramilitary group loyal to Saddam.
Group Captain Lockwood said there were also signs the Fedayeen had moved south from Baghdad ahead of the British troops to bolster the morale of the regular army.
"This hasn't been the case. The regular army has continued to surrender, and left these small pockets of Fedayeen and the Special Security Organisation, and these are the ones that we're dealing with.
"The irregular forces are lightly armed, yes, slightly troublesome, but we have the firepower and professionalism to take care of them."
The biggest problem on the British doorstep may well turn out to be Basra, Iraq's second city.
British Desert Rats have reportedly withdrawn from Basra, as other UK troops engage in fierce fighting on the outskirts of the southern Iraqi city.
The British accuse the Iraqis of placing their guns close to the civilian population.
BBC correspondent Caroline Wyatt, at the British forces headquarters, in northern Kuwait, said UK troops were encountering
"guerilla tactics" from Iraqi forces in Basra but insisted they were trained to meet such tactics.
"There is considerable resistance in some areas and the fighting is dirtier in some areas than could have been expected," she said.
Military sources clearly believe there are several hundred hard-core, well-armed Saddam Hussein loyalists holed up in the city.
That was why there were air raids over Basra on Saturday night.
But one British officer confided it is very difficult to bomb people's hearts.