The US President, George W Bush, has admitted that regular attacks on American troops occupying Iraq have created a security issue.
He said it required the United States to remain tough. He was speaking in Botswana on the latest stage of his Africa tour.
Three US soldiers were killed and another was injured in separate overnight attacks in Iraq.
Two soldiers were killed in Mahmudiyah, south of Baghdad, when they were ambushed with small arms fire at around 6.30pm yesterday.
A separate rocket-propelled grenade attack on a US convoy in Saddam Hussein's hometown of Tikrit, 175km north of the capital, at around 10.30pm killed one soldier and wounded another.
In other attacks overnight, mortars were fired at US positions in Ramadi, 100km west of Baghdad, apparently without causing any casualties.
A logistics base near Balad, 75km north of the capital, was also hit by mortar fire, leaving one vehicle badly damaged.
Residents in the flashpoint town of Fallujah also said that US positions had come under attack with RPGs and mortars overnight, without reports of any casualties.
But the US military said it was unaware of any incidents in the town.
