Police and eyewitnesses said the blast had been caused by fuel canisters on a truck in the Karrada district of the capital.
At least one police officer said the explosion had not been caused by a bomb
President Bush said Saddam Hussein will face the justice that he "denied to millions" but that his capture by US forces will not mean the end of violence in Iraq.
In a brief televised address, Bush said he had a message for the Iraqi people:
"You will not have to fear the rule of Saddam Hussein ever again."
Bush added that the detention of the former Iraqi president Saddam Hussein's did not mean that attacks against US soldiers would come to an end.
Earlier today a US occupation solider was killed whilst trying to detonate a bomb, US central command confirmed.