Huge explosions south of Baghdad shook buildings in the heart of the capital early on Tuesday as allied forces apparently bombed Saddam Hussein's Republican Guards.
A faint orange glow flashed on the horizon from the blasts, which started at midnight last night and came from where Republican Guard units are located. In Washington, Pentagon officials said US helicopters had begun attacking Saddam's forces arrayed around the city.
At about the same time, in northern Iraq, heavy bombing was heard from near the key northern city of Mosul, indicating that allied forces were hitting positions closer to the border with the Kurdish area.
Earlier in Baghdad, security and police officers dug more trenches around military offices in the centre of the Iraqi capital, as smoke from fires set to conceal bombing targets hung over the city.