A suicide bomber detonated half-tonne of explosives outside the US seat of power in Iraq on Sunday, killing at least 20 and injuring around 100 in the deadliest attack since the capture of Saddam Hussein.The blast in the heart of the capital came on the eve of a key meeting in New York between the UN, Iraq’s governing council and US and British officials over the country’s political future.It exploded near what the Americans call the Assassin’s Gate, the main entrance to the ‘Green Zone’, formerly Saddam’s Republican Palace complex and now the top-security civilian and military HQ of the US-led administration.The US confirmed at least 20 deaths, but the toll is likely to rise. More than seven hours after the blast, soldiers were pulling bodies from the wreckage as bulldozers shovelled debris and moved shattered cars. Officials said many of the bodies were too badly burnt to be identified.A US military spokesman said at least two American contractors were believed to have been killed in the blast.US Colonel Ralph Baker said a pickup truck packed with 454 kg of explosives blew up outside the gate, where vehicles and people were lined up waiting to enter. Hospitals around the capital said they had treated at least 110 people for injuries. US military officials said three US soldiers and three US civilians were among the injured.Most of the victims were employees waiting to be searched before entering the complex. ‘‘People were thrown aside, three here, five there. The dead were all workers,’’ said an eyewitness.Raqad Iyas Ibrahim cried sitting on a hospital bed: ‘‘I saw a car, I really don’t know what happened, I saw windows smashing, then I just fell. I can’t hear,’’ she said.As anxious Iraqis waited by the bombsite for news of relatives on Sunday afternoon, Iraqi soldiers handed out leaflets promising up to $2,500 for any information leading to the capture of those responsible for the attacks.Meanwhile, Danish troops in south Iraq said they had shot dead an Iraqi civilian who drove on when they tried to stop his car. In Tikrit, two Iraqis were killed on Saturday when a bomb they were planning to use against Americans exploded prematurely. Another blast on Saturday, 30 km north of Baghdad, killed three US soldiers and two Iraqi officials. The deaths took the number of US troops killed in Iraq since last year’s invasion to 500. —(Reuters)