Gunmen have killed two US soldiers and wounded nine others in a flashpoint Iraqi town.
US forces have been subjected to an increasing number of attacks
US military officials said a "hostile force" based in a mosque fired rocket-propelled grenades and small arms at a US Army unit in Falluja, 50 kilometres (30 miles) north-west of the capital Baghdad.
US Central Command (Centcom) says its soldiers responded decisively, killing two of the attackers and capturing six others.
Tuesday morning's attack was the latest of several such incidents in recent days.
Centcom said an American helicopter which landed to evacuate the wounded was damaged in a collision with a US armoured vehicle.
The Americans said that on Monday one soldier was killed and another injured when gunmen fired on a 3rd Armoured Cavalry Regiment convoy near the town of Haditha, about 180 kilometres (110 miles) north-west of Baghdad.
On the same day, a US military vehicle ran over a landmine on the outskirts of Baghdad. One soldier died and three more were wounded in the incident, which Centcom said appeared to be the result of hostile action.
A US military position in Baqubah, north of Baghdad, was also hit in a grenade attack, but no one was reported hurt.
US soldiers in the area subsequently shot dead a woman who was reportedly holding grenades and walking towards them, Reuters news agency quoted the US military as saying.
And in the town of Baiji, near Tikrit, the ancestral home of Saddam Hussein, a rocket-propelled grenade was fired at soldiers from the 101st Airborne Division, but the device failed to explode.
In other developments:
- US military officials say two more senior members of the former regime have been captured - Sayf al-Din al-Mashhadani, a Baath Party chairman and militia commander in Muthanna, and Sad Abd al-Majid al-Faysal, the Baath Party regional chairman for Salah al-Din
- The International Atomic Energy Agency says its scientists will arrive in Iraq this week to check reports of looting at the country's largest nuclear site
- Iraq's State Oil Marketing Organisation tells Reuters news agency that it aims to resume exports of crude oil by mid-June
- The US will urge Iraq's creditors to consider debt relief for the country at the forthcoming G8 summit in France, reports say
- Four soldiers are threatening to sue the British Ministry of Defence, claiming they are suffering symptoms akin to Gulf War Syndrome following the war in Iraq.
Falluja, a predominantly Sunni Muslim town, is a former stronghold of Saddam Hussein's regime which was toppled last month by a US-led coalition military force.
The town has been the scene of several clashes between US troops and Iraqi gunmen.
Last month, at least 15 Iraqis died in Falluja when US forces opened fire during demonstrations against the American occupation.
A subsequent grenade attack in the town wounded seven US soldiers.
In a statement on the latest incident, Centcom defended the use of force against targets in the mosque.
"The use of a religious site, such as a mosque or church, as cover for military purposes is a violation of the law of war," it said.
"Coalition forces strive to honour and respect the sanctity of religious places and locations such as Islamic mosques.
"However, coalition forces have an inherent right to defend themselves from attack, and will always seek to do so in such a way that causes the minimum amount of harm to innocent life, protected sites and civilian property."
The deputy head of the Anglo-American administration in Iraq has admitted that there are too few troops in the country to bring order.
Major General Tim Cross, the British number two in the Office of Reconstruction and Human Assistance, said there were particular problems in Baghdad, although he insisted they were being addressed.
"There's no doubt that bringing a nation back to life is not easy and we have had lots of difficulties, and we will have more in the days ahead," he said.
"But things are definitely getting better."
The administration's new "de-Baathification" policy, designed to root out the influence of Saddam Hussein's party, has also been criticised.
Ramiro Lopes da Silva, the United Nations humanitarian co-ordinator in Iraq, said the UN was drawing up a plan to
rehabilitate hundreds of thousands of soldiers who had been made jobless.
"We have to come up with something simple to absorb a potential
source of destabilisation," he said.
"If not, we reinforce the lawlessness and will raise banditry
not only in Baghdad but in rural areas."