A number of US soldiers were injured and two US Humvee vehicles were damaged as they came under RPG attack in the Khan Dhari area, 30 kms west of Baghdad, eyewitnesses told Aljazeera.
The attacks follows a deadly day for the US occupation forces in which two soldiers were killed and four others wounded in an ambush by suspected resistance fighters in Baghdad's Sadr City.
The US military said on Friday the attack happened on Thursday at 20:00 (17:00 GMT) and the dead soldiers came from the 1st Armoured Division.
A Shia militia group said earlier it had lost at least one of its men in a shootout with US troops on Thursday night in the teeming Shia neighbourhood.
The location of the latest anti-US attacks is significant because it may signify Shia Muslims are abandoning their stance of non-aggression towards the occupying powers.
Today's ambush in al-Sadr City brought to 154 the number of US soldiers killed in Iraq since Bush declared major combat over on 1 May. Many more have died in what the US military says are non-combat activities.
Nine people were killed in al-Sadr City, which is home to four million people, in a car bomb explosion at a police station hours earlier.
Aljazeera's Baghdad bureau said the anti-US violence followed a huge demonstration in al-Sadr City a few days ago by Shias angry at the Americans arresting two Islamic scholars.
"You can't say all the Shias are rising up against the Americans, but the people of al-Sadr City - who are influenced by Islamic cleric Muqtada Sadr - are very angry with the occupying powers," said Aljazeera's Ahmad Shuruf.
He added: "These are poor people and the effects of occupation are hitting them the hardest"
"The Americans have made a big effort not to provoke the Shia up to now, but things may be falling apart. I think today could be a very bloody day."
"The terrorists in Iraq believe their attacks on innocent people will weaken our resolve. They believe we will run from a challenge. They are mistaken. Americans are not the running
US deputy defence secretary
The deaths came after US Deputy Defence Secretary Paul Wolfowitz vowed America would not be deterred by almost daily attacks in Iraq, and declared US forces were winning their mission.
Wolfowitz, addressing an American conservative thinktank that honored him as a "liberator", said Saddam Hussein diehards and "foreign terrorists" were trying desperately to undermine Iraq's progress.
"The terrorists in Iraq believe their attacks on innocent
people will weaken our resolve. They believe we will run from a
challenge. They are mistaken. Americans are not the running
kind," he said.
"Our troops will not be deterred by the desperate acts of a dying regime or ideology ... We are winning," he added.
President George Bush has faced growing public suspicions he exaggerated the threat posed by Iraqi unconventional weapons to justify the war that ousted Saddam six months ago.
He is also being accused of mismanaging the Iraqi occupation as US troops are dying almost daily in attacks.
The White House, confronting falling poll numbers, has launched an aggressive public relations push aimed at
bolstering declining US public support for the Iraq mission.