A US marine was shot dead after being mistaken for the enemy, the US Central Command (Centcom) said in a statement on Wednesday.
US forces closed in on Monday on Baghdad in their bid to topple Saddam Hussein after moving past stiff resistance in southern Iraq.
The Iraq war is essentially over, but a nagging $ 200,000 question still casts a shadow over the US military victory: where is Saddam Hussein?
US intelligence officials intercepted phone calls of Iraqis that made them believe that the Iraqi leader was seriously wounded in a bombing raid.
US marines were still bogged down on Monday outside the southern Iraqi city of Nassiriya, the key to opening a second route north to Baghdad.
Iraqi President Saddam Hussein will shortly deliver an 'important and historic' speech to the nation, state-run television has announced.
The main northern Iraqi city of Mosul was rocked by three fresh US-led air raids early on Monday, the Arabic news channel Al-Jazeera said.
US forces seized three Iraqi presidential palaces, including Saddam Hussein's main facility in the heart of Baghdad.
Without a sample of his DNA or dental records, it would be difficult but not impossible to confirm the Iraqi leader's death, a forensic scientist said.
A US cruise missile targeted Iraq's Information Ministry early on Monday, apparently causing new damage to the ministry complex.
In a sign the fighting phase is over, strike forces who seized Baghdad will begin handing control to US Army regulars on Saturday.
A US commander said the troops had destroyed the Baghdad division of the Iraqi Republican Guard near Kut, 170 km southeast of Baghdad.
British forces battling to take control Basra are still facing resistance from around 1,000 Iraqi militia, along with regular troops.
President Saddam Hussein called on Iraq's tribes to fight the British and US troops without waiting for specific orders.
The US military said on Friday Iraq's entire 5th Army Corps had surrendered in the northern city of Mosul.