Bulldozers are still carefully sifting through the rubble of the Canal Hotel, the UN's headquarters in Iraq, in case there are any more bodies to find from last week's bombing. Those UN staff brave enough to stay on are working in tents outside the wreckage, under the searing sun.
But more than just the Canal Hotel is in ruins. Down among the rubble lay the last illusions that the American occupation of Iraq might be working. After a week in which Iraq's main oil pipeline to the north was set on fire, the water supply to Baghdad was sabotaged, and the UN's chief envoy, Sergio Vieira de Mello, was murdered along with at least 22 other people in what many are calling the worst attack on the UN in its history, no one doubts any more that the occupation here is in trouble.
It was made clear in the most savage way last week that the Americans and their allies are facing ruthless and organised resistance to their occupation. Yet it was also one of the Americans' most successful weeks in terms of their hunt for the former members of Saddam's regime. Both Saddam's former vice-president, Taha Yassin Ramadan, and, more importantly, Al Hassan al-Majid, the man known as Chemical Ali, were captured. That the news of their capture was overshadowed by the week's other events shows how successfully those responsible for the bombing of the UN headquarters have been able to change the agenda in Iraq. The story is no longer about the hunt for Saddam and his henchmen - it is about an occupation in danger of turning into a nightmare.
Outside the ruins of the Canal Hotel one Iraqi asked angrily: "Why did they attack the UN when the real target is before them?" He was pointing at the American soldiers. But the message from the ruins seemed clear: no one is immune in the hell the bombers want to turn Iraq into for the Americans.
Fear has taken hold of Baghdad. Westerners are leaving town, and humanitarian organisations are following the UN's lead and considering cutting their staff. The international Red Cross has put oil drums filled with sand outside its Baghdad HQ in the hope of slowing the approach of another suicide bomb truck.
The evacuation of the British embassy signalled that the only safe place for a Westerner is behind the massive fortifications the Americans have built around military bases. The American administrator in Iraq, Paul Bremer, insisted the bombing of the UN did not mean Iraq was in chaos. But it certainly looks that way.
With many ordinary Iraqis convinced the only reason the Americans are here is to "steal" the country's oil, the strike on oil exports last weekend was an appeal for popular support. Then came the body blow. At almost exactly 4.30pm local time on Tuesday, in what is now believed to have been a suicide bombing, the bomber detonated a Kamaz flatbed truck packed with 1,000lbs of explosives, along with some old shells and munitions to provide particularly damaging shrapnel, right under the third floor window of Mr de Mello's office at the Canal Hotel. The results were devastating. Survivors spoke of seeing dead bodies and severed limbs as they clawed their way out of the wreckage. Some had to dig their colleagues out of the rubble. The blast was so powerful it damaged a hospital for spinal injuries near the UN building, wounding paralysed patients.
The death toll stands at 23, but it may yet rise, with two workers missing and no record of the many visitors to the building at the time. For all the courage of its staff, the UN is facing a serious rethink of its mission here.
Everyone wanted to know who to blame for the bombing. Until last week the Americans blamed the daily attacks on their patrols on "remnants" of the Saddam regime and "diehard loyalists". But this time Donald Rumsfeld, the US Defence Secretary, claimed that hundreds of foreign Islamic militants along the lines of al-Qa'ida had arrived in Iraq and were behind the bombing. But no one has produced any evidence for that yet.
Meanwhile the Americans still refuse to acknowledge the existence of Iraq's own homegrown resistance groups, for which there is plenty of evidence: the videotaped announcements from them which appear several times a week on the Arab news networks; and the graffiti proclaiming their messages which have begun to appear on the walls along Baghdad's streets.
One or more of these groups could have been behind the bombing. Some groups are loyal to Saddam. But other Sunni Islamist groups are as hostile to the former regime as they are to the American occupiers. There has, so far, been no Shia resistance - but yesterday's killing of British soldiers in Basra shows that trouble is brewing there, too.
One group, which calls itself the Iraqi National Islamic Resistance Movement, released a tape shown on al-Jazeera the day the water pipe was sabotaged, in which it vowed "to kick out the occupiers as a matter of principle".
A previously unknown group calling itself the Vanguard of a Second Mohammed Army issued a tape claiming responsibility for the bombing of the UN building - but it is not clear whether the claim was genuine. Its message vowed to fight "every foreigner" in Iraq.
Unless the Americans produce some evidence to the contrary, it appears entirely possible that the UN bombing was the work of a homegrown Iraqi opposition to the occupation.
Whoever is responsible, the occupying powers are getting decidedly jumpy. The Americans have become engaged in an unseemly spat with the UN, accusing it of turning down offers of more security, and building a concrete wall too close to the building to protect against truck bombs.
Ramiro Lopez da Silva, the man effectively in charge of the UN mission after the murder of Mr de Mello, countered that it could not do the work it was here to do behind American guns and barbed wire. "We will always be a soft target," he told reporters.
The bombing exposed not just the shortcomings of the UN's own security, but the complete failure of law and order in Baghdad and much of Iraq. Even US soldiers have only been safe inside their heavily fortified bases; and it may be only a matter of time until some one works out how to attack one of those.
It seems very easy for someone who wants to get hold of high-grade explosives, pack them into a truck and carry out a suicide bombing. This is a city where most people are armed to the teeth and shopkeepers protect their stocks by sleeping in the shop with a loaded gun. I myself have seen looters rob a bus full of passengers in broad daylight on the road to Baghdad.
After a week of hell, the American occupying forces and everyone else in Baghdad is hunkering down nervously to see what the future brings. The illusions are gone now: there is serious resistance and this is going to be a hard occupation. Everybody fears there will be more bombings like the Canal Hotel. The question is: where?
The week in Iraq
Fires burn out of control after the main oil pipeline to Turkey and water supply line to Baghdad are bombed.
Suicide bomber detonates explosive-packed lorry next to United Nations headquarters in Baghdad, killing at least 23 people, including the senior UN official in Iraq.
UN humanitarian programme suspended indefinitely as search for bodies in rubble goes on. Polish troops withdraw from high-risk area amid fears of "new Vietnam".
US army announces capture of Ali Hassan al-Majid, number five on most-wanted list. Known as "Chemical Ali" after a gas attack that poisoned 5,000 Kurds, and "Saddam's Knuckles" for his part in dictator's purges.
America seeks wider international support for its occupation, but France and other countries refuse to send troops as peacekeepers while US insists on sole military command.
Three British soldiers killed and one seriously injured when their 4x4 vehicle comes under fire in Basra, bringing the number of UK deaths since the end of the war to 11.Reuse content