Some of Iraq’s best conventional forces have been routed by Allied bombing and ground fighting, but more lie between the advancing American troops and Baghdad, US military officials warned today.

Huge explosions rocked the heart of the Iraqi capital tonight, sending huge clouds of smoke over a building in the centre of the city and around the presidential Old Palace compound across the Tigris River.

Iraqi commanders are pulling troops out of the north of the country to back up Republican Guard units crippled by days of US attacks in the south, US defence officials said today.

US forces have been bombarding elite Iraqi Republican Guard positions south of Baghdad, a senior coalition commander said today.