Massacre of the peacemakers

The United Nations chief envoy to Iraq was killed yesterday by a massive suicide truck bomb that blew his office in Baghdad to pieces. Sergio Vieira de Mello was among at least 20 people killed in the bombing and the death toll is still climbing.

Many UN staff are still missing and rescue teams worked through the night searching the rubble for bodies. Among the dead was Fiona Watson, aged 35, from Pittenweem in Fife, Scotland, who was a political affairs officer in Mr Vieira de Mello's office.

The wing of the UN headquarters that housed Mr Vieira de Mello's office was obliterated. Where it once stood, a concrete roof was hanging precariously from the side of the main building. This was the day the American occupation of Iraq turned into hell. Mr Vieira de Mello and his staff, not part of the occupation forces but here to help the people of this ravaged land, were crushed by falling concrete and blown apart in their offices.

No one can remember an attack on the United Nations as devastating as this. Everybody in Baghdad is wondering who will be next. An immense cloud of yellow dust was still rising when we got there half an hour after the bomb went off, so powerful was the explosion. The truck was parked in an alley next to the wing housing Mr Vieira de Mello's office, fuelling speculation that it was a deliberate assassination. Or else, the target may have been the UN in general.

The sky was full of American helicopters coming to collect the wounded - at least 100 - and slowly they emerged, some with their clothes torn by the blast, some in shirts wet and heavy with blood. Mahmoud Shatr, a man I had met smiling and joking only a day before, stood splattered with the blood of wounded people he had dragged out from under the rubble. The dead may include not only international UN workers but locally hired Iraqi cooks, cleaners and security guards such as Mr Shatr, and journalists. The building was packed for a press conference when the bomb went off at almost precisely 4.30pm local time (1.30pm BST) yesterday. "There was a big explosion," said Mr Shatr. "I saw more than 60 wounded, about 20 of them seriously. I myself saw 15 people dead. There were four people trapped under the rubble but thank God we managed to dig them out."

Another survivor, who did not want his name printed, was still clutching his briefcase, white with dust from the building. His face and chest were still caked in his dried blood, hours later in a Baghdad hospital. "I don't know what happened," he said. "All I know is that there was an explosion and somehow we got out."

One woman, her clothes torn, was too frightened even to get into an ambulance and her injured colleagues had to help her on board. Iraqis desperately afraid for relatives who work inside the building, crowded around US soldiers, begging for information. Adaleh Tawfiq borrowed The Independent's satellite phone to call her daughter, Enas, inside. She was safe but the others did not know the right phone numbers for their relatives. Never Krikor, an elegant lady in a floral jacket, was terrified for her son, Rafi, and in a state of panic, calling out beseechingly for information no one could give her.

What came before was nothing to this. The daily rocket- propelled grenade attacks on American soldiers. The bombing of the Jordanian embassy. None of them killed so many people or sent a shiver of fear down the spine quite like this. "Why did they attack the UN?" one Iraqi asked angrily. "The real target is in front of their eyes." He gestured angrily towards the American soldiers trying to hold back the crowds.

Moments before the bomb went off the Americans were celebrating the capture of Saddam Hussein's vice-president, Taha Yassim Ramadan, but the bombing of the UN building completely overshadowed it.

There was no way of telling who was behind the blast. There will be speculation that Saddam loyalists were to blame but it could equally have been one or more of the Sunni Islamic resistance groups who oppose both Saddam and the Americans. It will serve to increase the chaos and instability on Baghdad streets and to increase the fear of American soldiers, of international aid workers, and of ordinary Iraqis. A sophisticated campaign to destabilise the occupation seems to be spreading.

Kofi Annan, the UN secretary general, insisted the UN would stay in Iraq despite the bombing. But with investigators still uncertain who is behind the bombing of the Jordanian embassy on 7 August, the indications are that it could get worse here yet.