It was, though, clear enough which way the wind was blowing as far as public opinion was concerned. Fears of a prolonged war may have unsettled the markets — oil prices firmed, the dollar sank and safe-haven gold and bond prices had risen when the New York Stock Exchange closed the night before almost 4 percent lower after setbacks for the allied forces in Iraq. (One analyst described it as “more volatile than a yo-yo — and about as intelligent as one”). But the prolonged skirmishes of the previous days seemed only to have hardened the resolve of the public. Support for the war in the latest poll increased to 54 percent with just 30 percent opposed.

If bad news was what shifted the public mood, Tuesday began with more. Overnight, the first British soldier killed in action was named as Sergeant Steven Mark Roberts of the 2nd Royal Tank Regiment; by 7.30 a.m. a second British combat fatality was announced. Reports from the field were of ferocious sandstorms — so bad the ground attack on Baghdad had been stalled, perhaps by as much as several days, with even more atrocious weather predicted. And in the early hours, American television networks began reporting intelligence sources had told them President Saddam has authorized the use of chemical weapons in defense of Baghdad — reports that the Pentagon, having it both ways, went on to deny.

As the day progressed, so did the storms. Swirling clouds of dirty-brown sand choked troops and reduced visibility at times to less than 20ft. The advance of the main armored column had been halted. They had also come up against President Saddam’s crack troops — the 30,000-strong Medina Division of the Republican Guard. Engaging them would mark a new phase in the war — but that could not be done without a massive aerial bombardment first.

The blinding sandstorms inhibited that. It was too dangerous for attack helicopters to fly. A dozen aircraft launched from the USS Harry Truman in the Mediterranean returned to the carrier a few hours later without reaching northern Iraq. But the weather did not inhibit the B-52s flying from Britain.

Throughout the night and well into the day, the bombers blasted the Medina Division positions to the south of the city. US-led air forces flew 900 strikes overnight, an increasing number against Republican Guards.

The bombs dropped were massive. The blast could be felt 20 miles to the north in Baghdad where shock waves were sent through the city from the distant bombardment, prompting panic as cars sped away and pedestrians raced for cover. So massive were the explosions, many in the capital speculated that the US military had used the Massive Ordinance Air Blast (MOAB), the biggest non-nuclear bomb in the world.

If the allied troops were able to get any rest, the delay would have been welcomed. Correspondents reported the soldiers were looking very tired after the dash to Baghdad, which is one of the fastest recorded in military history. What had become clear by Tuesday morning was which of the three-pronged advance on Baghdad was the main threat.

The first, led by the US Fifth Corps, had been along the western bank of the Euphrates approaching the capital through the Shia holy city of Karbala, 50 miles south of the Iraqi capital, close to where units from the Medina Division are located.

The second, moving up the other side of the river, was the one that had been stalled by unexpectedly stiff resistance in Nassiriyah, where US Marines has taken the heaviest casualties of the war so far. A third thrust, with the First Marine Expeditionary Force in the lead, is moving toward Baghdad between the Tigris and Euphrates; advancing toward Kut along two converging routes. Kut, which is defended by another group of Republican Guards, the Baghdad Division, was the scene of one of the greatest humiliations to befall the British Army when, in 1916, an attempt to reach Baghdad failed and some 13,000 British troops were captured after being besieged by the Turks in World War I. Few survived captivity.

Prospects look better this time, the British commanders hope. Some 500 Iraqis have been killed in the past two days in the sweep through southern Iraq. Allied generals Tuesday morning, acknowledged that, in the words of the Chairman of the Joint Chiefs of Staff, US Gen. Richard Myers, “we think the toughest fighting is ahead of us”. Fears by some military analysts that the swift advance has dangerously overextended and exposed the allied lines of support and supply are primarily based on the experiences in the Nassiriyah region where the most protracted clashes with Iraqi forces have been — and where US Marines have sustained their largest casualties so far. It is also where the only American prisoners-of-war were taken (apart, that is, from the two Apache helicopter pilots who were named as Chief Warrant Officer Ronald Young, 26, and Chief Warrant Officer David Williams, 30).

By Tuesday, though, things had begun to change at Nassiriyah. Although the area was still not totally secure, substantial numbers of US forces began to pass through the town. Over a two-hour period, a convoy of hundreds of tanks, armored vehicles and lorries passed through a protective corridor of armor in the hostile city and over the Euphrates to begin the 230-mile journey northwest to Baghdad.

Their difficulties were not over. Despite an air strike that killed at least 30 Iraqis, the convoy met a fresh ambush on the road north.

The ambivalence of the rest of the world to all this emerged in various forms. The South Korean Parliament will hardly have given cheer to Washington with its decision to postpone, until next month, a vote on sending non-combat troops to Iraq. And in Europe critics of the war continue to operate on a variety of fronts.

In Britain, the Archbishop of Canterbury, Dr. Rowan Williams, broke the silence he has maintained since fighting began with a critique of “the underlying weaknesses and moral inconsistencies that have led us to a situation where our leaders have concluded that we have no alternative to war”. He called for nations “urgently to develop better methods of working together” on international law, proposed a reform of the UN Security Council and pressed the need to rebuild “broken or threatened bonds of trust with allies not involved in military action”.

How far such healing has to come was clear from a newspaper article by Joschka Fischer, the German foreign affairs minister, who was scathingly dismissive of any attempts, postwar, to rebuild the world in the image of the United States. And the announcement that France would unveil proposals this week to give greater powers to the European Commission showed the contrary direction in which thinking was going in Paris.

Back on the battlefield, things were changing to the south in Basra. Early Tuesday, British military commanders announced that the status of Basra had changed. The city had now become “a military objective” because of the amount of resistance encountered there. Originally, the plan at Basra was to isolate the city and bypass it. The hope was only small pockets of trouble would be encountered in the mostly Shiite city where, in 1991, the people rose up against President Saddam and his largely Sunni followers. (That uprising in Basra was brutally crushed by the Iraqi military). Tuesday, the plan changed. “Our intention is not to siege the city, for sure,” US Maj. Gen. Victor Renuart said at the command headquarters in Qatar. “Our intention is to return security to the city. There will be elements in the city that will be military targets — the Fedayeen, special Republican Guard forces, Baath Party forces that are fighting.” A main element in the plan was an attempt to break the grip of ruling Baath Party militia and other forces loyal to President Saddam in the area, said Air Marshal Brian Burridge, the senior British officer in the Gulf. Overnight a “lightning strike” had been made on party buildings in nearby Zubayr where a top Baath official had been seized.

It was separately announced that a British soldier from the 1st Battalion The Black Watch had been killed in action in an operation near Zubayr.