Tuesday's car bomb attack on the UN headquarters in Baghdad is evidence that Iraq is descending deeper into chaos, reports Jihan Al-Alaily from Baghdad A car bomb devastated a large portion of the UN headquarters in Baghdad, killing the special representative of the secretary-general, Sergio Vieira de Mello and at least 20 other UN local and foreign staff on Tuesday. Victims were evacuated by American military helicopters and were initially treated at Al-Rashid American field hospital in Baghdad. There has been international outrage over the bomb attack, one of the worst terrorist incidents targeting the UN in its 58 year-old history. No one has claimed responsibility though Iraq's 25- member Interim Governing Council blamed the bombing on either followers of toppled President Saddam Hussein or foreign terrorists. The bomb blasted a 12-foot by 5-foot crater in the ground, shattering the façade of the Canal Hotel used by the UN and shattering glass in the neighbourhood for several miles. Up to 100 people were wounded in the blast and many people are feared trapped in the rubble. UN staff in New York, Baghdad and around the world mourned the death of the veteran Brazilian diplomat, the 55-year-old de Mello, and other colleagues. De Mello was wounded as he lay trapped under the rubble. He was said to have been contacted immediately after the blast but bled to his death later. The UN Secretary-General Kofi Annan denounced the bombing as an "inexcusable act of unprovoked and murderous violence". Annan, who referred to de Mello and the other dead UN staff as "some of the most outstanding public servants", vowed to continue UN work in Iraq. "The least we owe them is to ensure that their deaths have not been in vain. We shall continue." But the secretary-general appeared to indirectly criticise the United States which, as the occupying power, has a mandate from the Security Council to restore law and order. "We had hoped that by now the coalition forces would have secured an environment for us to be able to carry on... economic reconstruction and institutional building," he said. "That has not happened." The US administrator in Iraq, Paul Bremer, said following the attack that security measures would be re- examined. The bomb laden truck is believed to have hit the western wall of the UN compound, directly beneath the political section where de Mello's office was. The narrow road leading to the western side of the compound was not blocked and questions will be raised as to why such a lapse in security was allowed to happen when the other sides of the UN compound were heavily protected. Iraq is quickly descending into chaos that some fear is orchestrated in order to increase the pressure on the US- led coalition forces to depart, as one political analyst who requested anonymity claimed. The car bomb attack on the UN compound comes two weeks after a similar attack on the Jordanian Embassy in Baghdad that left 17 dead. It also comes in the wake of two attempts at sabotage, involving a central water main in Baghdad and an oil pipeline. The latter sent oil fires billowing and caused massive environmental damage in Anbar state. Many fear the increase in acts of sabotage will setback badly needed UN humanitarian and reconstruction work. Many Iraqis have mourned the loss of Sergio Vieira de Mello as an "honest broker" who in less than four months had played an instrumental role in broadening the responsibilities of Iraq's Interim Governing Council (IGC) beyond what was envisioned by the Coalition Provisional Authority (CPA). In his last public press conference de Mello spoke about latent tensions over Iraq between the US and the UN and described relations with the CPA as "business- like, constructive and open". He described the context of Iraq, a founding member of the UN that is occupied by two Security Council members as "unique and unprecedented". The context in which the UN is trying to help he qualified as "delicate and... indeed bizarre". De Mello, in an interview with Al-Ahram Weekly exactly one month ago stressed that the UN would like to see sovereignty restored to Iraqis as soon as possible and made an impassioned plea to neighbours and critics to give a chance to the IGC "to assume fully the executive responsibility". De Mello's visit to Egypt ten days ago was the last leg in a regional tour aimed to urge co-operation with the IGC and to dispel what he called "huge misperceptions and misunderstandings" about what is truly happening in Iraq. Only a week ago de Mello boasted of a small success when he announced in a press conference following his return from Egypt that Arab League secretary-general, Amr Moussa, indicated to him that he would prepare the General-Secretariat to receive members of the IGC to engage in a dialogue that de Mello called "essential". This came after the League's special committee meeting on Iraq made it clear that it did not believe it could recognise the IGC as a legitimate government of Iraq.