The latest attack was in Habaniya, just north of Baghdad where eyewitnesses told Aljazeera a military base came under mortar fire.
"Mortars were fired at the base and US forces, using heavy-machine guns fired back but there were no casualties," the eyewitnesses said.
Earlier in the day, a US soldier was killed and six wounded in a landmine explosion near Mosul in northern Iraq, a military spokeswoman said.
Another convoy was attacked in Ramadi, west of the capital Baghdad, killing one soldier and wounding two more.
The Bush Administration had expressed hope that attacks against US troops would end following the killing of Udai and Qusay Saddam Hussein.
The attacks brought to 41 the number of US soldiers killed by Iraqi resistance since Washington declared major combat operations over on 1 May.
"Saddam Hussein's sons were responsible for torture, maiming and murder of countless Iraqis. Now more than ever all Iraqis can know that the former regime is gone and will not be coming back," Bush said.
Meanwhile, Dubai-based al-Arabiya television channel on Wednesday broadcast a taped message purportedly from ousted Iraqi President Saddam Hussein in which he vowed that the war against the US-led occupation forces was not over.
The message stated it was recorded on 20 July, two days before the killing of Saddam Hussein’s two sons, Uday and Qusay.
"The war (against the US-led forces) is not over. The war is not finished," warned the voice on the tape.
"The only correct assertion will be when the enemy officially announces that the war is not finished because the war is not yet over, politically or militarily," it said.
In the last few weeks, many audiotaped messages from Saddam have been aired over Arabic TV news channels.